20 and 25 feet. A sea-wall has been partially destroyed, but there are no groynes, and sand is removed from Robert's Cove at low water. The neighbourhood of Reanies Bay and Kinsale Harbour is stationary, but between Hake Head and the Old Head of Kinsale low sandy cliffs have been levelled and covered by the beach within the last five years. The coast from Courtmacsherry Bay westwards to Clonakilty Bay is undergoing continual and obvious erosion where unprotected by rocky cliffs. At the eastern end of Broadstrand in Courtmacsherry Bay the sea flows over a spot where thirty-five years ago houses were to be seen; an advance estimated at about 30 yards. One mile westward at Blindstrand a road formerly crossed from Lislee village to Coolbawn, on the opposite side of the strand. This is now 130 yards outside the present high-water mark, and it is estimated that during the last thirty years 16 acres of land have been lost. Coast-defences have not been neglected: the Board of Public Works built a wall 200 yards in length on the eastern side of Blindstrand to save the village of Lislee, and the local railway company another on the river Argidean to protect their property. The remainder of Clonakilty Bay and the coast westward past Cape Clear as far as Mizen Head is a stable region of bold rocky cliff's broken now and again by sandy beaches and coves. The coast is unprotected, but little material is removed, and no alteration is on record except a slight gain of land around Schull, where the spring tides do not run so far up into the land as once they did. The rugged and indented coast of Bantry Bay and the Kenmare River is without observations, but from Ballinskelligs Bay northward the records are fairly complete. Between the last-named inlet and Brandon Head the changes are but few. The waves at the north-eastern end of Ballinskelligs Bay have to some extent worn away the cliff at exceptionally high spring tides. There are no groynes, and the taking of sand from the beach appears to produce no appreciable effect. In front of Ballinskelligs C.G.S., on the western side of the bay, a loss of 2 feet is recorded in the four years preceding 1899. A pier close by is suggested as being the cause of this erosion by collecting shingle on one side and producing thereby an eddy which does the damage. No shingle is removed. On the southern side of Dingle Bay, between Coonanna Point and Rossbehy Point, the sea encroaches, especially in the winter with southerly or south-westerly gales. The cliffs under the Bathing Cottages at Rossbehy were protected by large blocks of concrete, joined with railway-irons and balks of timber. These having no effect, large concrete blocks were sunk in the sand and boards placed from one to the other; but at the date of the report (August 1899) the time had been insufficient to test the effect of this arrangement. Losses occur in both Dingle and Smerwick Harbours. In the former a sea-wall formerly existing on the north-eastern side has now been washed away, and also a portion of the adjoining land, while abreast of the town and public road walls have been built to prevent encroachment. In Smerwick Harbour for a stretch of a mile (viz. from Ballynagall Point to Murriegh) a cliff of average height of some 12 feet is crumbling through the action of the sea, which has broken into an old public road and rendered it almost impassable. The fishing-pier at Ballynagall has probably retarded the erosion of the banks in its vicinity. Local loss of land is reported from the C.G.S. at the mouth of the Casheen River, and north of the mouth of the Shannon along the stretch of coast between Kilkee and Milltown Malbay. The annual loss from Goolen to Doonbeg Bridge (Kilkee) is given as 6 inches, an estimate derived from information given by the older fishermen, while northwards it is rather greater, in Mal Bay, where the cliffs are less high than to the south and interspersed with low and sandy coast. Some sand is removed and no groynes have been built. The northern shore of Galway Bay and the Aran Islands show no change (small quantities of sand are removed), but the southern shore from Kilcolgan Bridge northward for 30 miles is undergoing gradual erosion. The vertical range of ordinary spring tides may be summarised by taking the averages of a number of observations at adjacent points. The figures (in feet) are as follows:-In the Solway Firth 22-5, falling off to 15 in Wigtown and to 9 off the Ayrshire coast and towards the Firth of Clyde. On the Caithness, Sutherland, coast the readings are 15, decreasing to 13 in the Moray Firth, to rise to 16 off Peterhead and Aberdeen. A lowering of about 2 feet takes place towards the Firth of Tay to rise again to the same level (16) off the Haddington coast, whence there is a gradual decrease of about 3 feet to Hartlepool. At the mouth of the Humber, however, the range is 19 feet (21.75 at Barton); but while maintaining an 18 or 20 feet range at the entrance to the Wash the variation is much lower off the East Anglian coast (say 7·5), thence gradually increasing to 18.75 round East Kent. The highest reading on the southern coast is in the neighbourhood of Hastings (24); the lowest on the southern side of the Isle of Wight, and towards Portland (7·5 and 9·8 respectively). Once more the range rises to about 16, which is maintained to the North Cornwall coast, where the figures again increase (1875) to 27.5 in North Devon. On the Glamorganshire coast we find 33.8, in the southern part of Cardigan Bay 12, on the North Welsh coast 19, and in Liverpool Bay 27.5. The variations in Ireland are less conspicuous, in Galway Bay 12.5, decreasing slightly as we go northwards, and being decidedly less between Malin Head and Belfast Lough (87 to 7·4). Southwards the range increases to 14.6 off County Down, 118 off County Dublin, and varies between 13.25 and 11.75 off the southern coast. In this report little or no description is given of the nature of the coast. Mr. Wheeler's book supplies this defect for England, while, in judging from the reports sent in, it is often doubtful how closely a general description of the coast can be applied to any particular part which is undergoing change. The writer concluded that details of this kind would not add materially to the value of the report and would greatly increase its length. [Since this Report was read at the Southport Meeting, Mr. R. G. Allanson-Winn has published various criticisms in letters to the Times, Daily Express, and other publications, and has sent numerous communications on the subject to the Committee. It has been thought best, however, to allow the Report to be published as it stands, and any corrections which may be found necessary, either in the information supplied by the Coastguard Service or in the deductions drawn from it, can be inserted in the next Report submitted to the Association.] Occupation of a Table at the Zoological Station at Naples.-Report of the Committee, consisting of Professor G. B. HOWES (Chairman), Mr. J. E. S. MOORE (Secretary), Dr. E. RAY LANKESTER, Professor W. F. R. WELDON, Professor S. J. HICKSON, Mr. A. SEDGWICK, and Professor W. C. MCINTOSH. Report on the Occupation of the Table during February, March, April, and half of May, 1903. The Oocyte of Tomopteris. By WILLIAM WALLACE, B.Sc. AT Naples I studied the earlier stages of the oogenesis of Tomopteris onisciformis, Esch., and particularly the changes in the germinal vesicle during the growth of the oocyte. Since Eschscholtz discovered this species in 1825, several naturalists, including Claparède, Vejdowski, Carpenter, and Fullarton (1895), have dealt with the genital products of Tomopteris, and have described the more obvious features of the oogenesis, such as the following : 1. The origin of the ovaries in the rami of the parapodia by proliferation of cells of the cœlomic epithelium. 2. The detachment from the ovary and discharge into the cœlom of balls of cells. One cell of each cluster, increasing in size, becomes the oocyte, while the remainder-some half dozen or so-continue attached to the larger cell, and constitute the 'nurse-cells.' 3. The growth of the oocyte (apparently) at the expense of the group of nurse-cells, which is soon no more than a cap or small appendage at one pole of the egg. These nurse-cells finally degenerate and disappear. Such phenomena are not diagnostic of the oogenesis of Tomopteris, but have been described for other Polychaetes, such as Ophryotrocha (Korschelt 2), Onuphis (Bergmann 3), &c. The cytological changes accompanying the growth and maturation of the egg of Tomopteris do not appear to have been studied hitherto. Some observations on this head may accordingly be of interest. The material at my disposal was, thanks to the kindness of Dr. Lo Bianco, tolerably abundant. The species, however, does not seem to be so plentiful here as, for example, at St. Andrews, where, during certain seasons, large quantities are found in the tow nets. Neither were the ripe female specimens so large at Naples. All that I had to deal with were under a centimetre in length, whereas at St. Andrews the specimens commonly attained a length of two or three centimetres (if I remember rightly). In all the Neapolitan specimens I examined numerous gregarines occurred, mostly in an encysted condition in the epithelium of the gut. I studied the eggs in the fresh state, when, like the whole body of Tomopteris, they are transparent. I also studied them in serial sections. of fixed material. 1 Fullarton, Zool. Jahrb. (Spengel's), Morph. Abth., viii. Bd., 1895. • Bergmann, Zeit. für wiss. Zool., Bd. lxxiii., Hft. 2, 1902. The following points were made out in the larger eggs before treatment with reagents. The eggs are perfectly spherical and transparent. The nurse-cells, if still present, occupy a small area at one pole. There is no follicle around the egg, but an extremely fine membrane (? zona)—which therefore, as Bergmann points out for Onuphis, must be an independent product of the egg itself is present at the surface. In the cytoplasm just under the membrane minute highly refracting droplets, probably of oil, can be discerned. They are often in clusters and of various sizes. In the very centre of the egg is the perfectly spherical germinal vesicle with a single highly refractive germinal spot or nucleolus. Occasionally one or two smaller refractive bodies (the 'neben-nucleoli') may be seen within the germinal vesicle. The position of the germinal spot is invariably eccentric. Vacuoles varying in number and size could be distinguished in the nucleolus, except in the case of the largest eggs. The nucleolus of the full-sized eggs was notably smaller and at times contained a small vacuole. The nucleolus, therefore, enlarges up to a certain point in the growth of the oocyte and then diminishes. Its complete dissolution was not observed. The space between the germinal vesicle and the egg membrane is filled up with yolk spheres. These are nearly uniform in size, and almost touch one another, leaving very little protoplasm between. The spheres are not very highly refractive, and are therefore only vaguely discernible in the fresh egg. In the germinal vesicle of the full-sized eggs one can distinguish, besides the nucleolus, certain nebulous or flocculent masses. These are the definitive chromosomes. To see them in the fresh egg requires a certain intensity of light and careful focussing. By the addition, under the cover-glass, of an aqueous solution of methyl green more facts were brought to light. As the green solution reaches the eggs these swell up somewhat and burst their membranes. Often the yolk is extruded in small drops through the substance of the membrane, the external surface of which is accordingly studded with drops. This observation seems to indicate that the egg membrane of Tomopteris, like the zona radiata of vertebrates, is perforate. The protoplasm flows out through a rupture in the capsule slowly, sometimes in long strings like a syrup. The yolk spheres entangled in it generally adapt themselves to the size of the aperture and pass out intact. On coming in contact with the watery solution they break down and flow together. The yolk spheres are, I think, evidently viscid drops of some albuminous substance. Inside the egg the syrupy protoplasm in which the spheres are imbedded appears quite homogeneous and translucent, but as it flows out into the watery methyl-green solution minute granules (microsomes) come into view in its interior. It is probable that, as Wilson has observed in the case of certain Echinoderm and Annelid eggs, the yolk of the Tomopteris egg forms a true emulsion in Bütschli's sense. I cannot, however, definitely state the existence of microsomes in the cytoplasm of uninjured eggs, i.e. before contact with the methyl-green solution. Probably they are naturally present in this transparent egg and only require a coloured solution, like methyl green, to show them up. Wilson, Journal of Morphology, vol. xv., Supplement, 1899. Turning now to the germinal vesicle, after treatment with methyl green. This body is often extruded intact. As the green solution reaches it, minute refringent granules in constant dancing motion come into view. After oscillating for some time these granules settle down and arrange themselves in a network formation. Here again, as in the case of the microsomes, it is not very easy to say whether the granules pre-existed in the natural state of the egg. In the meshes of the network larger granules (? lanthanin of Heidenhain) were seen. None of these minute granules stained with the methyl green; in fact, the only structures in the nucleus which take up this stain are the chromosomes (strong) and the nucleolus (faintly). The chromosomes appear to be rings or loops of irregular form. They are very thick and roughly moniliform-very different in appearance from the smooth outlined attenuate loops depicted by Korschelt in the nearly ripe egg of Ophryotrocha. I counted four chromosomes in full sized eggs of Tomopteris. Korschelt gives the same number for Ophryotrocha. The numerous unstainable granules in the full-grown germinal vesicle of Tomopteris appear to correspond to Heidenhain's oxychromatin granules, while the substance of the chromosomes-which stains with methyl green— is basichromatin. Besides the larger eggs, oocytes with chromatin in the primitive spireme stage were examined after treatment with methyl green. The spireme stains intensely. In somewhat older oocytes with reticular nucleus the nucleolus lies eccentrically in the nucleus, and is surrounded by a vacuole to the walls of which it is moored by radiating threads of the network. The growth of the nucleolus keeps pace with the growth of the germinal vesicle and of the oocyte. It is at first homogeneous, but becomes gradually more and more vacuolated. These small vacuoles fuse to form a single large eccentric vacuole. Finally, in full-sized eggs, the nucleolus is smaller, and contains no large vacuole. It seems probable therefore that the decrease in size is due to the collapse of the vacuole and discharge of its fluid contents into the nucleus. For sections various methods were tried. The fixing agents employed were chiefly Mann's picro-corrosive-formol mixture, Gilson's mercuro-nitricacetic fluid, Hermann's fluid, and Boveri's picro-acetic. The Hermann preparations were stained with thionin or safranin. The others were variously treated, the chief combinations employed being Heidenhain's iron-hæmatoxylin with orange green, Delafield's hæmatoxylin with eosin or congo-red, borax carmine and picro-nigrosin, and nigrosin and 'light green.' On the whole, perhaps the best results were obtained with material fixed in Boveri's picro-acetic and stained with nigrosin and light green. The latter is a very rapid staining method, and gives a good chromatin-achromatin differentiation. It suffices to stain for one and a half minute in a saturated aqueous solution of nigrosin, and then for half a minute in an alcoholic solution of light green.' By this method only the chromatin proper stains black, while the nucleolus and the cytoplasm stain green. The nucleolus is especially prominent in these preparations, appearing as a shining green body. The nucleoli both of the germinal vesicle and tissue cells, such as the epithelium of the gut, stain similarly with the light green, and do not take up the black. Nigrosin, however, does not distinguish between oxychromatin and Heidenhain, 'Ueber Kern und Protoplasma,' Festschr. für Kölliker, 1892, &c. |