arises-Did these slender and minute structures build the fabric they present, and live on stems of Crinoids; or is their condition an accidental phenomenon by mere temporary adhesion or contact? V. Vermilia minuta, Brown, These fabricless inhabitants

of ancient oceans, in their shadowy shrouds might excite the imagination and please the visionary in his dreams. Did they perform any significant or important office?

To smooth, unworn Crinoids-not to the tattered and torn, like faint images in a mirror, scarcely more substantial-they seem to have clung, and, martyr-like, performed their last wriggle, not after any pattern, but variously; and like man, have fulfilled their allotted span in the same space in history-they lived-they died.

VI. Crania quadrata, M'Coy. In the sediments of the old seas the broken and dismembered stems of a Crinoid were the special throne of the Crania, although other debris was not rejected. The attached valve is generally almost exclusively found on these stems. If it were important, the proportion might be vaguely ascertained. In 30 instances, for example, attached to well-preserved fragmentary Crinoids-not to worn or abraded fragments-28 present the attached valve, and only 2 specimens of both valves. In the majority of examples little is left of the shelly matter, and one is left involved in a web of Stenopora tumida. Of the free valve, on a small stem, two examples occur; one evidently bearing the free valve compressed; another specimen, deemed very rare, has during life been encroached on by an enlarging basal portion of Crinoid, or the union of several, and would have been covered had not the vital energy of the first occupant apparently necessitated a deviation from the common plan by continued and forcible resistance, causing the Crinoid to disperse its required structure on either side, free of the living Crania-which nevertheless perished, as it would seem, through its confined and restricted action and growth. The phenomenon is unique as far as known.

VII. Discina nitida, Lamarck. On a fragment of stem of a Crinoid only one Discina (with both valves), indifferently preserved, has been seen, and, consequently, in this connection, it must be found rarely. It is, however, by no means rare, and is often found in small ironstone nodules beautifully preserved. It is found, also, on shells, sometimes in groups.

As light dawned the original stock of organic substances, long

laid aside, as found on Crinoids, decreased-the basal portions of the Crinoid, when recognized in its hydra aspects, having alone obscured several genera of imagined structures.

II.-On Fresh and Brackish-water Ostracoda, chiefly from the West of Scotland. By Mr. DAVID ROBERTSON, F. L.S., F.G.S.

This paper, being a contribution to the "Fauna of Scotland," published by the Society, is printed separately.

III.-Notes on the Occurrence of a species of Boring Marine Alga penetrating the Shell Structure of a species of Productus. By Mr. JOHN YOUNG, F.G.S.

Mr. Young stated that, while preparing specimens of a Productus for microscopic examination of the shell structure, he had occasion to remove the outer surface of the shell with weak acid. After this was done, he found that the inner layer, in many of the specimens, had been burrowed by a minute parasitic organism of a tubular character. These borings on the surface are scarcely visible to the naked eye, but when examined under a low power of the microscope, are seen to branch in certain directions by bifurcation of the tubes as they pass through the inner layers of the shell. In some of the specimens the dark matter filling the tubes is seen to terminate in rounded points: some of the branches also present a moniliform structure of tube; while others, viewed in cross sections on the etched surfaces of the shell, appear as a series of black round dots. Mr. Young stated that at first he was inclined to regard these perforations as the work of a minute burrowing sponge, but he had found that a similar organism which had been found perforating the structure of Silurian and Devonian corals and brachiopods, as well as corals from some of the more recent formations, had been described by Professor P. M. Duncan, F.G.S., in the Quarterly Journal of the Geological Society of London, for May, 1876. Professor Duncan, in his paper, regards these perforations as the work of a unicellular alga, parasitic within the structure of the organisms, and clearly related to Achlya; and he distinguishes the form found in the palaeozoic rocks as Palaeachlya perforans. After a close comparison of the Carboniferous organism with that figured by Professor Duncan, Mr. Young was inclined to

regard it as the same, as it agreed in all essential particulars, except those which would naturally arise out of differences in the form and structure of the kind of organism penetrated. To distinguish the Carboniferous form from that already described, he proposed to call it Palaeachlya perforans, var. carbonaria, as it appears to have been a little more robust than the older form.

Mr. James Neilson, jun., also showed an interesting series of Chonetes Laguessiana from Roscobie, Fifeshire, which, under the partly eroded surface of the outer shell, showed numerous perforations of, apparently, the same boring alga. Mr. Young had also found it in the shell structure of Productus costatus, a Carboniferous limestone fossil, as well as the last named.

APRIL 29TH, 1879.

Professor John Young, M.D., F.G.S., President, in the chair. Mr. John Smith, Stobbs, Kilwinning, was elected a corresponding member, and Mr. Christopher Sherry an ordinary member.

SPECIMENS EXHIBITED.

Mr. John Young, F.G.S., exhibited a series of Conodont remains and Sponge Spicules from the Silurian and Devonian limestone strata of England, forwarded by Mr. John Smith, Kilwinning, corresponding member, who had sent for exhibition, at a former meeting of the Society, an interesting series of conodonts and various forms of sponge spicules, which he had found in the limestone strata around Dalry, Ayrshire. Since that time Mr. Smith had visited several districts in England, and had been successful in discovering the remains of conodonts in some of the weathered shales and limestones of the localities he had visited, and which curious remains had not, so far as he knew, been formerly noted as occurring either in the Silurian or Devonian formations of England. Very little is yet known of the nature of the organisms that have yielded these conodont remains, which consist of small teeth, jaws, &c., of many different forms, one authority referring them to the jaws of annelides, another to those of myxinoid fishes, or to the lingual armature of certain forms of mollusca or the

maxillipeds of crustacea. As new localities for these interesting though obscure forms are being found, it is to be hoped that more light will soon be thrown upon the true nature of their origin.

Mr. Young also exhibited a series of beautiful plates he had received from Mr. Thomas Davidson, F.R.S., Brighton, illustrating a number of new and rare forms of Carboniferous brachiopoda from the West of Scotland, which he is preparing for the supplement to his great work on the Fossil Brachiopoda of Great Britain, upon which he has been busily engaged for the last 30 years. Among the specimens figured in these plates, Mr. Young called the attention of the members to a small species of Productus which he had found at Brockley, near Lesmahagow, and to a small species of Chonetes from Corrieburn, Campsie. The former had been identified by Prof. de Koninck, of Liège, as his Productus Griffithianus, found first at Vise, in Belgium, but which has not previously been recorded for Britain. The second had been identified by Mr. Davidson as Chonetes gibberula (M'Coy), and also new to the Scottish list.

Mr. Henry C. Young exhibited the following spiders new to Scottish lists:

Steatoda bipunctata, Linn. One specimen, a male, taken in the window of a cellar at Port-Dundas on 14th June, 1878.

Agroëca proxima, Cambr. One male, taken on a hedge bank at Kilmalcolm on 4th September, 1878.

Neriene rufipes, Sund. Two females, taken in the neighbourhood of Glasgow in June, 1878.

Linyphia zebrina, Menge. This spider was exceedingly common among herbage in every locality visited during last summer and

autumn.

Linyphia pallida, Cambr. One specimen found at roots of grass near Hamilton on 22nd August, 1878.

Epëira agalena, Walck. A male and female of this species were taken at Aviemore, Perthshire, in July, 1878, by Mr. J. J. King.

Xysticus ulmi, Hahn.

A male of this species taken among grass

on the cliffs, Arbroath, in September, 1878.

Tarentula miniata, C. L. Koch. One specimen, a female, taken at Prestwick, by Mr. F. Alexander, in July, 1878.

Heliophanus flavipes, C. L. Koch. Two specimens, females, taken in the neighbourhood of Glasgow in June, 1878.

PAPERS READ,

I.-On the Mammalia of Scotland. By Mr. EDWARD R. ALSTON, F.Z.S., F.L.S., F.G.S., Corresponding Member.

This paper, which forms a portion of the "Fauna of Scotland," published by the Society, is printed separately.

II. On the Archaeology and Natural History of Tory Island. By Mr. J. A. MAHONY, Corresponding Member. With two Plates [III. and IV.].

What Iona is to Scotland, Tory is to Ireland. The archaeological remains of the Irish island are not in so good a state of preservation as those of Iona, but do not yield to them in interest. It is therefore of importance to chronicle them, as well as to have a full record of the Natural History of so remote an island; but this has not hitherto been done. The readiest way to get to the island is from Ballinass, near Falcarragh. This place is 42 miles from Londonderry by road. Arrived at Ballinass you make arrangements for a small boat to take you to the island, the "regulation" cost of which is 20s. From Ballinass to Tory the distance is 10 Irish miles, and the journey is, of course, not unattended by danger; but, with a breeze from the S. W. or S.E., is pleasantly performed in two or three hours. The writer has visited the island six times, and on two occasions only experienced any trouble in returning. Southerly gales kept him a prisoner for a week at one time, and for five days at another.

Tory is two and a-half miles long, and about a-quarter of a mile broad at its western extremity. There it is level, but on the east it rises into towering headlands 200 feet high-these cliffs (or "tors," as they are called by the natives, and which may account for the name of the island) being of the boldest and most fantastic shapes.

The usual place of landing is at the Camus, where the first thing to attract notice is the Round Tower. Nothing has been done to preserve this interesting ruin from the ravages of time, and its original height cannot now be accurately ascertained. It was examined, however, by Mr. Edwin Getty, in 1845, and at that time the pileus or cap was partly standing. He gives the height at 51 feet, the outer circumference at 51 feet 6 inches, and the diameter 17 feet 2 inches.* Every winter now brings down some of the

* Ulster Journal of Archaeology, Vol. I., p. 146.