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One that I found in a field, could only hop, being quite unable to fly, and another one was found shortly afterwards in the next field in the same condition. The weather at the time was severe, but the cause of this mortality was undoubtedly disease.

the exception of the wren and redbreast. The blackthorn has faded from the hedgerows, its place now taken by the milk-white hawthorn, which looks in its full as if a snowstorm had been and left great bunches here and there in every hedgerow. Sometimes the flowers of the hawthorn are pale red, which look lovely in contrast with the white. The apple-trees and the wild apple or crab are now looking their best, soon in their turn to wither and die.

(To be continued.)

NOTES FOR APRIL 1890, BEING AN EXTRACT FROM

A LETTER.

THE LUMINOSITY OF PLANTS.

WILL

The greater and lesser periwinkle were both in flower the beginning of this month. Lilac leaves also about this date ; and the hedges are now getting forward in leaf. Young rooks were hatched about the Ist of April, as I find by egg-shells thrown out of the nest. What a large quantity of sticks the rooks drop when busy building, either from their not being suitable, or by accident ! There is enough wood lying under a few elm trees (which contain a small rookery of about eighteen nests) to last a person for lighting a fire every morning for a fortnight. Snowdrops and crocuses have all disappeared now from our gardens. An interesting fact connected with the Christmas-rose I have lately observed in our garden. This plant was in flower about Christmas-time here, and were all faded away, when about the end of March I saw with surprise another flower half opened, which had shot forth from the stem where the flowers of December had died off, and now (April 7th) I notice others on some of the other stems, so that it seems as if it flowers twice in a season. There is now nothing more pleasant than to ramble through the meadows on a clear evening at this time of the year. The rich and clear song of the blackbird reaches us from some leafing hedgerow a little way off, where he sits perched on the top of some bush, cheering his less dusky spouse, as she is keeping guard over her blue eggs, snugly placed in the nest at the bottom of the bush. During the second week of this month the currant and gooseberry bushes: came into flower. Ground-ivy was in flower on the 9th, song-thrush with young on the 10th. Fieldfares I observed on the 13th, also a large flock of them the day before. Cowslips were in flower under hedges on the 13th, and dog-violets and wood-anemones were in flower on the same day. The ivy-leaved speedwell abounds amongst the green orn in a cornfield called “Mill-ditch." Blackthorn was in flower on the 13th of this month along the hedge at the bottom of the same field.

By CANON RUSSELL.
TILL you kindly allow me to bring under

notice some facts connected with the luminosity of plants which have been recently attracting my attention? I became acquainted with them quite accidentally, in the following way.

On the evening of the 16th of June, 1889, I happened to be taking a stroll round the Rectory Garden, and passing by a fine plant of the common double marigold (Calendula officinalis) of a deep orange colour, I was struck by a peculiar brightness in the appearance of the flowers. After watching for a few seconds, I observed, to my great surprise, that corruscations of light, (like mimic lightning) were playing over the petals. Thinking that I might be only the victim of an ocular illusion, I brought out other members of the household, and asked them to report exactly what they saw. Some perceived the flashes readily enough, but others only slowly and alter patient observation, all eyes not being equally sensitive to such rapid vibrations of light.

These performances commenced about 8.30 P.M. and continued for perhaps under an hour. I afterwards ascertained, that much later on, when it was almost dark, the whole plant seemed to glow with a sort of pulsing phosphorescence. The common nasturtium, and the scarlet geraniums showed a like luminosity. Closely connected with their appearances, I could distinctly see a blue vapour of extreme tenuity given off from the leaves of some of these plants, if not from all, in open daylight or under lamplight. This can be best seen by holding' the leaf against a dark background, and letting the light fall upon it at various angles. These two last phenomena were not as readily detected by other persons as were the sparks of the marigold. They were made, however, abundantly evident to all eyes in the following way. I put a leaf of the nasturtium on the stage of a microscope-and, having focussed it for the central spot from which the nerves branch off, under an inch and a half objective, I brought it into a room nearly dark. Looking at it then through the microscope I found that the leaf could be distinctly seen almost by its own light. The appearance

1

MAY.

The trees are now putting on their summer dress, and the hawthorn scents the evening gales. The anemone, primrose and violet have faded away, but others have taken their places, such as the blue-bell, or wild hyacinth, purple orchis, germander speedwell, and tormentil. The birds are as yet singing merrily in the hedges and groves, but in a few months' time all our singing birds will be silent with

another paper.

of the luminous vapour floating over its surface (like indicated by Mr. Lord, which, I think, should not moonlight over rippling water) was strikingly beau- be allowed to pass without comment in the pages of tiful. The whole leaf seemed to twinkle with points SCIENCE-GOSSIP. of light—the main ribs radiating from the common I would first point out that, by some misundercentre, shining out like a silver star. These effects' standing, Mr. Lord assumes that Mr. Gosse's phrase are best witnessed after a day of hot sunshine. Some “habitual protrusion of the head,” refers to some further facts and suggestions which may point to a inability of the rotifer to withdraw its head between possible explanation of these phenomena I reserve for the plates of the lorica. It is true that the figure

(after Ehrenberg) of Distyla: Horne manni in "The Supplement” represents this species with its head

protruding and its cilia extended, although otherwise REMARKS ON DISTYLA, WITH DESCRIP- much retracted, but I am inclined to deny credence TIONS OF THREE NEW ROTIFERS. to that remarkable position until I see some Distyla

assume it. On the contrary, Mr. Gosse's words can By David BRYCE.

only mean that as compared with the very sluggish, N a recent article (SCIENCE-GOSSIP, Sept. 1890), timid or indolent habits of the Cathypnæ, the Distylä

my correspondent, Mr. J. E. Lord, expressed are more usually active and less prone to indulge in his suspicion that the genus Distyla is not a good naps (?) when under observation. All the Distylæ I one, and he described as Cathypnæ two forms of have seen were perfectly able to retract their heads which he remarked that, “when retracted they are within the lorica plates. undoubtedly Cathypnæ, when extended as certainly In the next place, Mr. Lord appears to have would they be described as Distylæ.” He further overlooked the fact that Eckstein founded the genus

IN

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A

X320.

Distyla in 1883; and it has therefore priority over B

Cathypna instituted by Mr. Gosse in 1886, at the

same time that he set apart the family of the Fig. 180.-Distyla depressa. Fig. 281.-Ditto, lateral. Dorsal view, extended.

Cathypnadæ, to include not only Cathypna, but, inter

alia, the Distyla of Eckstein, which he thus distinctly suggested that some if not all of the species of accepted and confirmed. If, therefore, the distincDistyla are but extended Rotifera of the genus tions set up between the two genera were shadowy Cathypna.

or insufficient, it would be the genus Cathypna that I had hoped that ere this some other observer would have to give way, not the genus Distyla. would have been induced to plead the cause of Again, if a species be so balanced between two Distyla, but, behold, Jove thundered and lesser genera as to appear to belong to one when extended, tongues were mute.

and to the other when retracted, there can be no For myself, I cannot claim to have examined more question that the extended position being the than five or six species of the two genera in question, natural one, the species must be assigned to that and my remarks are perhaps to be regarded as genus to which it conforms when extended or active, provisional rather than as final. Yet there are points and I submit that on Mr. Lord's own showing, his two species are certainly Distylæ, and his description less complete and no points are to be seen; and I and figures as certainly indicate that genus.

have found dead specimens of the same species, from I observe that in his quotation of Mr Gosse's which the head and all interior parts have vanished, remarks about Distyla, he omits the word lengthened. yet displaying an apparently permanent shell much Mr. Gosse says “the lengthened and flattened form.” exceeding that shown in retraction. I conclude that The omission is of course unintentional, but the the restricted use of the term may be convenient but character is important and fits Mr. Lord's species. is possibly incorrect, and that the absence of the two

As to the distinctions between the two genera, lateral points is a character that especially requires these have been set forth in such a plain and concise caresul verification. way in the criticism of Mr. Lord's article which Although among some genera of the Rotifera mere appeared in the December issue of the Journal of the size is an unsafe guide to identification, there are Royal Microscopical Society, that I may perhaps be others in which, regard being had to mature permitted to quote the sentence for the benefit of individuals only, the dimensions of the different those who have no opportunity of seeing the original. species are closely adhered to. Among the Cathy“In Cathypna the whole trunk is loricated and the pnadæ I have found the variation to be very slight, creature when extended is dorsally arched ; but not I think more than 10 per cent., if so much. It in Distyla only the hinder portion of the trunk would therefore be an assistance to those who hope is loricated, the forepart having a membranous covering and the creature, when extended, is comparatively flat, or, as it is termed, depressed.” Save that the writer omits to draw attention to the usual outline of the two genera when extended, Cathypna

Fig. 187.-Monostyla

cornuta. X 320.

Fig. 184.-Monostyla arcuata.

Ventral view. X 320.

Fig. 185.-Ditto, dorsal

view.

Fig; 186. -Distyla musicola.

entral aspect. X 480.

being generally ovate, and Distyla of the form of a long ellipse, the above sentence persectly and briefly summarises the points of difference.

All other points in the generic characters are, I think, either common to both genera, as “lorica closed behiod, toes two, selvage-like thickenings of the lorica around the fout," or of secondary import. ance as depending upon individual estimate, such as lateral inangulation strong or feeble, or of habit, such as "the habitual protrusion of the head” and “the more constant activity.” All these may be safely disregarded, when there are present the leading characters pointed out in the sentence quoted.

There appears to be some confusion as to the meaning of the term lorica, in respect of the genus Distyla. I am not myself quite clear that it ought to be restricted to that portion of the covering of the trunk, which appears to remain stiff and hard when the animal is retracted. I have found that different individuals of the same species do not always retract to the same degree, that whilst at one time two short lateral points (as described in many species) are easily visible, at another time the retraction will be

to meet with Mr. Lord's forms, if he would state particulars of the measurements when extended and when retracted. is also useful to know the exact shape and length of the toes. There is in nearly every genus, one point in which the species appear to agree to differ. In the genus Macrotrachela it is the spurs, in Distyla and Cathypna the toes.

I append descriptions of two species, which appear to me very distinct from any of those yet described, and of a Monostyla closely related to, but not identical with, the common and well-known M. cornuta,

Distyla depressa. Sp. Ch.—Lorica much flattened, ovate, truncate at both ends; anterior edges, ventral excised in moderate curve, dorsal straight; two short lateral points shown in extreme retraction ; dorsal plate shorter than ventral and narrower behind ; toes blade-shaped, acute, slightly decurved ; brain three-lobed.

a

The lorica is very flat, the average thickness of Aberdeen. Along with it were many examples of fairly niatured specimens being rather less than one- this Distyla, some Callidina elegans, and some others. fourth of the length of the dorsal plate. It is free The threc forms named continued to flourish up to from flutings or tesselation and moderately firm. In the end of November, when the severe weather retraction the outline of the trunk is scarcely altered, wrought havoc among the colony. The Distyle the proportion of loricated to membranous covering succumbed, but the other two species survived and being unusually great. In lateral view some irregular now after thirteen months the stock seems fairly wrinkles are visible in the integument lining the vigorous. It is noteworthy, that the supply of water lateral infold, which is well-marked (see dotted lines has never exceeded two ounces, any loss from Fig. 180), although the plates are but little separated. evaporation having been simply replaced from time The dorsal plate, while in front as broad as the to time from the household supply, that no artificial ventral, is rather narrower bebind, and is abruptly feeding was resorted to, and that no pond weeds were and somewhat convexly truncate. The ventral plate present, the plant side of the balance of life being is excised anteriorly, permitting the head to be bent represented principally by Scenedesmus and down as shown in lateral view. The outline is scanty growth of Oscillatoracev. posteriorly completed by the dilated basal foot-joint,

Distyla musicola. which appears to be almost fixed and to have even less freedom than usual in the genus. It is difficult

Sp. Ch.-Lorica ovate, flattened, both anterior to trace lines indicating the junction of this joint

edges truncate, almost straight, two very short lateral with the trunk on either dorsal or ventral side, but

points seen in utmost retraction. Dorsal plate rather those I have shown are, I think, correct. Indeed,

broader and longer than ventral, and rounded behind. the joint is little more than a partly shelly, partly

Ventral plate with a definite and shelly central portion membranous framework protecting and supporting

almost plane, from which a less stiff integument the sub-square lower foot-joint, which issues from the

recedes laterally to the edge of the infold, and under side and pivots on a blunt point arising from posteriorly merges into that of the dilated basal joint the ventral plate. The toes, seen vertically, are

of the foot. Toes, tapering, acute, without claw or widest at the base, are then slightly pinched in,

shoulder. again widen and finally taper to acute points without

Numerous dead examples have occurred amongst either claws or shoulders. This curvature is confined

the sediment of water drained from Sphagnum, but I to the outer edges ; the inner being quite straight,

have only as yet found one living specimen. The yet with a slight rugosity near the base. Seen

remains seen have however shown the creature in laterally the upper edges are decurved and the lower every position, and I find that as in D. depressa the nearly straight.

outline of the trunk is not greatly changed by retracThe ample brain is in front bluntly pointed, but

tion, and that extended the form is that of a long widens into three lobes, of which the central is the

oval, rather than that of an ellipse. The head is greatest and bears near the inner side at its base the wedge-shaped, the face rather prone, and the mastax bright rose-red eye. The wedge-shaped outline of normal. Some very delicate markings can somethe prone face is interrupted by two knob-like pro.

times be seen on the shelly portion of the ventral jections whose nature and origin I have been unable

plate. The membranous lining of the infold is so as yet to determine. The powerful mastax is well

wrinkled as to give a peculiar scalloped appearance forward, and I believe I have seen the jaws slightly

to the lateral margins. The basal joint of the foot is protruding into the buccal cavity. An oesophagus of

as in D. depressa, but even less distinct. The lower moderate length is attached to the inner side of joint is much narrowed at the base. The blunt point mastax and passing down it, proceeds to the stomach,

on which it pivots, appears however to arise from the the lower part being in constant and rapid undulation. upper joint and not from the ventral plate. The The stomach, surmounted by the usual gastric glands,

toes are thickest just above their middle and taper is separated by a distinct constriction from a capacious

thence to fine points. They appear straight in vertical intestine, and in both ciliary action is apparent. The

view, but seen laterally, they are slightly decurved, vascular system embraces lateral canals, at least three with upwards-turning points. pairs of vibratile tags, and a small contractile vesicle Length, extended, estimated at zoo inch ; retracted having a short period. Two band-like muscles pass

são inch; breadth, são inch ; toes, todo inch. from the head down the back. Length ;-total,

Habitat, among roots of Sphagnum, Epping ulo inch, toes about go inch, breadth zo inch.

Forest. In a gathering made in March 1890, from the

Monostyla arcuata. River Lea, below the Lea Bridge Waterworks, and Sp. Ch.-Lorica ovate, moderately depressed ; which I had placed on one side, I found some months occipital edge shallowly, pectoral edge deeply excised later a flourishing colony of Rotifera. The species in somewhat bow-shaped curve. Toe rather bladewere few but very select, the most conspicuous being shaped tapering to an acute point, without claw or Adincta oculata, only hitherto found, I believe, near shoulder.

This species resembles very closely the widely distributed M. cornuta and differs from it principally in being about one-fourth smaller, and rather narrower in proportion, and in having both the anterior edges of the lorica excised and to a greater degree. Mr. Gosse states that in M. cornuta the front of the lorica is shallowly incurved, that the anterior dorsal edge is slightly less incurved than that of M. lunaris, but that the ventral edge has its margin quite straight. I think that here he is slightly in error, and partly on this account, and partly for the sake of comparison with the figure of the new species, I add an outline of the ventral aspect of the lorica of M. cornuta when retracted. This position (not figured by Mr. Gosse) shows the straight occipital edge and the very slightly excavate pectoral edge of the lorica as well as the large basal foot-joint. In the numerous examples I have examined, the occipital edge has always seemed straight and the pectoral slightly excavate, and this structure is exactly what would be necessary to facilitate the bending downwards of the head.

In any case, in M. arcuata, the excision of both anterior edges is much sharper than in M. lunaris. In all other details, in general aspect when extended, and in its sluggish habits, the species is the counterpart of M. cornutu, yet the differences noted, though minute, are constant, and I consider fairly entitle the form to rank as distinct.

Mr. Gosse gives the length of M. cornuta as Ibo inch extended. The largest specimens I have measured were about 143 inch, and the average Tšo inch, while M. arcuata in the like position averages dio inch, the lorica alone being about gšo inch. I have found dead specimens very abundantly among the drainings from Sphagnum and I have recently had for a little time a colony in a jar, the bottom of which was covered with some threads of moss, gathered last year and now springing into fresh growth.

My sketches show a broad and a narrow form, apparently the extremes of variation, the former being probably a more mature individual. Young specimens resemble when slowly gliding along, the form which I take (yet with some doubt) to be the M. mollis of Mr. Gosse, which however when in retraction s not to be distinguished from M. cornuta and is therefore equally distinct from the present.

Habitat among roots of Sphagnum, Epping Forest.

school of naturalists, that this supposed factor in the transmutation of species is unproven and unnecessary ; unproven because the hereditary transmission of characters acquired during the lifetime of the individual has never been experimentally established, and unnecessary because we can explain the phenomena of organic evolution without invoking its aid ?

Such is the question which, of all others, is now engaging the attention of the biological world. Closely connected with it is the consideration of Professor Weismann's brilliant' contributions to the existing literature of variation and heredity, including a theory of heredity absolutely inconsistent with the conclusion of Mr. Darwin which we have quoted. For the last two years and a half, that is since the discussion on the transmission of acquired characters raised by Professor Ray Lankester at the Manchester Meeting of the British Association in 1887, in which Professor Weismann himself took part—this subject has been prominently before English naturalists. During this period there has been no paper or discussion on the subject, hardly even a reference to it, in the pages of SCIENCE-Gossip.* It is obvious that the question is one of the deepest interest, affecting, as it does, the very foundation of our conception of organic evolution. If the “ Lamarckian” factor, as it is sometimes called, is a true factor, it must have played an important part in the modification of species. If we are to reject it altogether, a large number of phenomena will have to be explained in other ways; in fact its rejection will entail a more or less important modification of the Darwinism of Mr. Darwin. Apart from these considerations, Prosessor Weismann's theories of heredity, variation, etc., which differ essentially from those hitherto generally held, are concerned with matters lying at the root of any explanation of evolution. I therefore thought that a series of papers on the subject, which should aim at setting forth, as briefly as possible, the various problems involved, would be of interest to those readers of SCIENCE-GOSSIP who

lack the time or inclination to study the subject more deeply. The method I propose to pursue is, first to state clearly the main question at issue, which turns on the truth or falsehood of what is known as Lamarck's “second law," and to sketch the present position of opinion upon it, then to give an outline of Professor Weismann's hypotheses on the subject of heredity and variation, and finally to try and show the exact bearing of these theories on the question with which I started.

We will commence our brief account of the position of opinion on the subject under discussion, and of how it came to be what it is, by stating the question at issue and then defining our terms. The question in its most general form is : “Can an 'acquired' character be inherited ?"

may

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* The above was written in April, 1890.

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