CONCHACEA.] 
MOLLUSCA. 
95 
I found this new British species immediately under the 
columnar greenstone rocks, west end of Arthur’s Seat, near 
Edinburgh, plentiful in a ditch at the Wells of Weary, which 
is now covered up by the railway. 
4. PiSIDIUM APPENDICULATA, pi. XXXIX, f. 25. 
Cyclas appendiculata, Leach, MSS.; Turton, Man., p. 15, f. 
6 ; Pisidium Henslowianum, Thompson, Ann. and Mag. Nat. 
Hist., VI, p. 54; Tellina Henslowinana, Sheppard, Linn. Trans., 
XIV, p. 150. 
Shell obliquely oval, much inflated; with regular, well defined, 
concentric grooves ; beaks very tumid, considerably produced, 
and somewhat tubercled. Length an eighth and a half of an 
inch ; breadth not quite a quarter. 
Found in slow running streams, but is very rare. 
This shell seems nearly allied to P. obliquum, from which, 
however, it differs, in its greater convexity, and the protrusion 
of the beaks, at the base of which is a groove, or dark zone, 
giving them the appearance of tubercular appendages. 
5. Pisidium nitidum, pi. XXXIX, f. 26. 
Pisidium nitidum, Jenyns, Monog., p. 16, pi. 20, f. 7, 8; 
Thompson, Ann. and Mag. Nat. Hist., VI, p. 53. 
Shell suborbicular, or slightly oval; umbones large, and blunt; 
external surface very glossy, of a pale horn-colour, and covered 
with fine, concentric striae, which are wider-set and deeper on 
the umbones. 
Inhabits Battersea Fields, some ditches in Cambridgeshire, 
and ditches near Worcester; in a pond at Wolf hill, near Belfast, 
and other places in that neighbourhood; Lough Gill, County 
Sligo, Portarlington, and Finnoe, Ireland. 
6. Pisidium pusillum, pi. XXXIX, f. 27- 
Pisidium pusillum, Jenyns, Monag., p. 14, pi. 20, f. 4 and 6; 
Thompson, Ann. and Mag. Nat. Hist., VI, p. 53 ; Cyclas pu- 
silla, Turton, Brit. Biv., p. 251, pi. 1 1, f. 16, 17 ; Ib., Man., p. 
16, pi. 1, f. 7 ; Alder, Mag. Zool. and Bot., II, p. 119. 
Shell nearly orbicular, slightly ovate, subcompressed ; ura- 
bones prominent, and very obtuse at the points ; sides some- 
what flattened, and very slightly inequilateral ; surface of an 
olivaceous-brown, with very fine, concentric striae. 
Inhabits ponds near London, and many other localities. In 
Ireland, according to Thompson, it is the most common of the 
genus, frequenting ponds and drains. 
7. Pisidium cinereum, pi. XXXIX, f. 28. 
Pisidium cinereum, Alder, Cat. Sup., p. 4 ; Ib., Mag. Zool. 
and Bot., II, p. 119; Thompson, Ann. and Mag. Nat. Hist., 
VI, p. 54. 
Shell compressed, subovate ; umbones but slightly produced, 
obtuse at the points, is sometimes capped; lower margins of 
the valves meeting at an acute angle ; surface of a grayish ash- 
colour, and finely striated concentrically; with a few super sulci, 
which form deeper transverse zones. 
This shell is more ovate in its form than any of its conge- 
ners, excepting the P. obliquum, and will be at once recognized 
by being more compressed than them, and by its ashy hue. 
Variety 1. Somewhat more ventricose, with the umbones a 
little more produced. 
Inhabits ponds near Newcastle, and other localities in the 
North of England. Mr. Thompson says it is widely spread 
throughout Ireland, although no where common. He par- 
ticularizes Holywood House, Downshire ; Youngrove, near 
Middleton, County of Cork, by Miss M. Ball; Killereran, 
County of Galway, and Portarlington, by the Rev. B. J. 
Clarke ; and neighbourhood of Dublin, by Thomas William 
Warren, Esq. 
Sub-Division. — Tenuipedes. 
The mantle barely united before ; foot small, narrow, and 
compressed ; shell having but a moderate gape. 
Family I. — Nymphacea. 
Having never more than two primary teeth in the same 
valve ; shell often gaping slightly at the lateral extremities ; 
ligament external ; umbones generally projecting outwards. 
Section I, — Destitute of lateral teeth. 
Genus 17 Crassina. — L each. 
Shell suborbicular, transverse, equivalve, inequilateral; hinge 
with two strong, divergent, primary, large, central teeth in the 
right valve, and one small, nearly obsolete tooth, together with 
an indistinct, lateral one in the left valve; two ovate or oblong, 
remote, lateral, simple, muscular impressions in each valve, with 
a third very small one, situate immediately below the indistinct 
lateral tooth, or at the end of the posterior external depression, 
and in some instances mingling with the lower termination of 
the posterior muscular impression, which is always simple, and 
not sinuated. 
1. Crassina Danmoniensis, pi. XXXVIII, f. 1. 
Crassina Danmoniensis, First Ed., pi. 18, f. 1; Lamarck, V, 
p. 554 ; Venus Danmonia, Montagu, Sup., p. 45, pi. 29, f. 4 ; 
Crassina sulcata, Turton, Biv., p. 131, pi. 11, f. 1, 2 ; Astarte 
Danmonice, Fleming, p. 440 ; Astarte Danmoniensis, Forbes, 
p. 50. 
Shell strong, thick, subcordiform, subcompressed; with many 
regular, obsoletely striated, strong, equidistant, transverse ribs ; 
intervening furrows rather deep, quite smooth; umbones nearly 
central, anteriorly reclined, and rather acute, with a deep, 
lanceolate lunule under them ; surface covered with a dark 
reddish-brown, strong epidermis ; inside white, but not glossy, 
except round the margin, which is finely crenated, and very 
blunt at the edge. 
Found on the Devonshire, Welsh, and Northumberland 
coasts; also the Friths of Forth and Clyde; Lough Strangford 
and Portmarnock, Ireland. 
2. Crassina Scotica, pi. XXXVIII, f. 9- 
Crassina Scotica, First Ed., pi. 18, f. 9; Turton, Biv., p. 130, 
pi. 11, f. 3, 4; Venus Scotica, Montagu, Sup., p. 44; Maton 
and Rackett, p. 81, pi. 2, f . 3 ; Lamarck, V, p. 600; Astarte 
Scotica, Fleming, p. 440; Forhes, p. 51. 
Shell thick, subcordiform, subcompressed ; umbones nearly 
central, considerably rechned anteriorly; beneath them a lance- 
olate, subcordiform lunule ; surface with many regular, rather 
elevated, somewhat parallel, transverse ribs, which are narrowed 
towards the posterior side ; whole surface covered with a thick, 
yellowish-brown epidermis, but reddish-brown in others; inside 
smooth, white ; with the margin plain. 
