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OSTRACODA. Ostracoda were abundant in many of the beds ; and I regret my inability to have them thoroughly worked out for the present Report. Mr. Joseph Wright kindly examined material from the various strata at Alexandra Dock, and obtained the following result :ABBREVIATIONS :-vr, very rare; r, rare; f, frequent; c, common; vc, very
Pontocypris mytiloides, Norman,
villosa, G. 0. Sars,
- impressa, Baird,
IIIIIIIIIIIIIIIIII Red Sand.
Several of the species above-named are now very rare in our waters, and one, Cythere whiteii, has not yet been detected.
In Stewart's Paper a single species, Cythere albo-maculata, is recorded as occurring in the clays both at Belfast and Magheramorne.
1 See Malcomson, “Recent Ostracoda of Belfast Lough,” Proc. Belfast Nat. Field Club, 1884-5, Appendix.
The only other note of Ostracoda from the estuarine clays that I know is in the "Monograph of the Post-tertiary Entomostraca of Scotland" by Messrs. Brady, Crosskey, and Eobertson, published by the Palaeontographical Society in 1874, in which (p. 102) a Table is given showing the distribution of these forms obtained at various depths in blue clay from excavations in Belfast Harbour, and which, in order to make my enumeration complete, I reproduce here :—
"Balanus balanoides, Linn. Examples of this species from the Belfast clay are in Canon Grainger's collection.
B. porcatus, Da Costa. On shells in a number of the deposits—of frequent occurrence at Belfast.
* Verruca ttromia, Miiller. Recorded by Grainger from the Belfast bed (Creusia verruca).
Cancer pagurus, Linn. Portion of a large claw of this Bpecies was found at Alexandra Dock.
Portunus depurator, Leach. Claws, &c, at Alexandra Dock; rare.
Carcinus moenas, Leach. Remains of this crab are somewhat common. They occurred at Alexandra Dock and "West Bank, Kilroot, Magheramorne, and Larnc.
Anomia ephippium, Linn. Generally distributed, and characteristic of the upper clay, though absent from the Lough Foyle and Downpatrick beds. A beautiful Pecten-formed specimen from Alexandra Dock was four inches in breadth, var. aculeata occurred at "West Bank and Alexandra Dock; var. sguamula was found occasionally.
A. patelliformis, Linn. Recorded from Belfast by Stewart on Grainger's authority. Bell has noted it from Magheramorne. Two valves occurred to me at Alexandra Dock, var. striata. A single valve at Alexandra Dock.
Ostrea edulis, Linn. Occurred at almost every station, and generally of large size. At Alexandra Dock, and Spencer Basin (Stewart), thickly-packed layers of shells occurred; its immense profusion at Magheramorne has been referred to on a previous page, var. parasitica. Grainger records fine specimens from the Belfast bed; and a shell obtained at Alexandra Dock is referable to this variety.
var. hippoput. Immense shells of this solitary deep-water variety characterize the Thracia clay at Belfast and Magheramorne. Some single valves at Alexandra Dock weighed from 1 lb. to 2 lbs. each; and a huge valve in the Belfast Museum, also from the Belfast clay (which, however, appears partially mineralised), weighs 5 lbs.
Pecten putio, Linn. Two fine single valves at Alexandra Dock, one of which measured If inches in length.
P. varitu, Linn. An abundant species, being present in all but the Scrobicularia clays. Generally of fine size; but the Downpatrick specimens, though mature, were very small. At Magheramorne pure white examples are frequent; but the number of ribs, which is invariably from 28 to 30, excludes them from belonging to the P. niteut of Macgillivray.
var. purpurea. Occurred at Alexandra Dock and Magheramorne; some specimens attaining a length of 2} inches.
P. optrcularis, Linn. In the estuarine clays is less abundant than the last species; it occurred at Eglinton, Magheramorne, Belfast, and Greenore; being abundant in the Belfast bed. An example from Magheramorne has a breadth of 3 inches, and bears four Anomia plugs, two on each valve.
P. maximus, Linn. In the beds at Downpatrick and Greenore, fry only occurred. At Belfast and Magheramorne, full-sized examples were common. A fine specimen from the latter station measured 7\ inches in breadth, and in the fine mud taken from between its closed valves over 45 species of Foraminifera, Ostracoda, and Mollusca were counted, including 18 species of the last-named division.
Lima loteombii, G. B. Sowerby. A single valve of this species occurred in clay from the Magheramorne bed, among a large number of its congener L. hian».
L. hiam, Gmelin. Abundant in the Magheramorne deposit. Thompson, Hyndman, Grainger, and Stewart, successively, have recorded it as occurring very sparingly in the Belfast bed; but it did not occur to me there. It does not appear to now live on the Northcast of Ireland coasts.
Mytilut tduJit, Linn. Common in most of the deposits, and absent from none of them, except the Newcastle bed.
var. pellucida occurs occasionally.
M. modiolus, Linn. Abounds in the Magheramorne bed. Very rare at Eglinton, and occurred sparingly to Stewart and the writer at Belfast. At Magheramorne it does not share the exuberant growth of many of the bivalves there, being uniformly about inches long, whereas its normal length is 5 inches; full-grown specimens are common in our present waters.
M. adriaticus, Lamarck. Found sparingly at Magheramorne by Stewart and the writer, and at Belfast by Grainger in addition.
♦var. ovalii. "Occurred in excavating a channel in Belfast Harbour, and may be considered a newer Pliocene fossil."—Jeffreys. Brit. Conch., vol. n., p. 117. "Some specimens dug out at the site of the new floating dock appear to belong to this variety."— Stewart.
Modiolaria marmorata, Forbes. Somewhat abundant at Magheramorne; very rare in the clays at Newtownards, Lame, and Limavady Junction. At Belfast, Stewart found it sparingly at Spencer Basin, and the writer at West Bank.
Crenella decussata, Montagu. This rare and beautiful little northern shell, characterized by Dr. Gwyn Jeffreys as an " exquisite gem of a mollusk," first occurred to me in the Magheramorne bed, where it is very rare. At Larne, in a bed of gray sand underlying the estuarine clay, a number of fine examples were obtained. Its presence at these two stations shows the persistency of species in certain limited areas, since this shell is one of the very few that Hyndman's dredging party obtained alive in Larne Lough.
Nucula sulcata, Bronn. Bell has recorded this species from Magheramorne. I did not find it there, but obtained a fine single valve at Alexandra Dock, and a smaller valve in the Downpatrick bed, and one or two at Lame. It is not recorded in a recent state from the North of Ireland.
N. nucleus, Linn. A characteristic shell of the Thracia clays, which usually yield it in abundance. Occurs in the deposits of the Loughs of Foyle, Lame, Belfast, and Strangford.