S88 
MOLLUSCA. BIVALVIA. 
LlMi^ko 
Gen. XCV. LIMA. — Shell longitudinally oblong, with ears ; 
beaks remote ; ligament external. 
385. L. fragilis. — Shell with irregular longitudinal rough 
ribs ; the ears oblique. 
Pecteii frag. Mont. Test. Brit. Sup. 62 — L. bullata, Turt. Biv. Brit. 217- 
t. xvii. £ 4, 5. — On different parts of the coast, rare. 
Length sometimes exceeding an inch and a half ; breadth an inch ; white ; 
valves equal, little raised ; one side with the edge straight ; the other arcu- 
ated ; ribs numerous, unequal, irregularly grouped, most prominent on the 
middle of the shell, and rendered rough by the irregular lines of growth ; 
margin nearly smooth ; beaks prominent. This shell (which may prove a 
var. of Ostrea glacialis of Poli, Test. 11. t. xxviii. f. 19, 20.) was observed by 
Montagu on the coast of Devon, afterwards by Dr Turton, at Bray, in Ire- 
land ; and more recently on the coast of Scotland, near Appin, by Captain 
Carmichael. — A single valve, communicated by the last observer, is lj%ths 
of an inch in length. 
386. L. suhauriculata. — Shell finely striated longitudinally, 
the ears nearly rectangular. 
Pecten sub. Mont. Test. Brit. Sup. 63. t. xxix. f. 2. — L. sub. Turt. Biv. 
Brit. 218. — On different parts of the coast, from Devon to Zetland, 
rare. 
Length |ths ; breadth |th of an inch ; pellucid, nearly equilateral ; two 
conspicuous mesial opake strije ; margin slightly crenulated. 
EXTINCT SPECIES. 
1. L. gibbosa Elongated, gibbose, smooth, longitudinally plicate in the 
middle; ears undefined — Sower. Min. Conch, t. clii. — Under Oolite. 
2. L. rudis Obovate, oblique, with seven longitudinal costae ; anterior 
ear open with thickened lobes — Sower. Min. Conch, t. ccxiv. f. 1. — Middle 
Oolite. 
3. L. antiquata Elliptical, depressed, coarsely striated; anterior ear 
deeply wrinkled, o^&n.~Sower. Min. Conch, t. ccxiv. f. 2. — In Lias. 
4. L. proboscidea — Broad, ovate, convex, with twelve ribs, each furnished 
with several large tubular processes ; ears small — Sower. Min. Conch, 
t. cclxiv. — Inferior Oolite. 
% 
Gen. PLAGIOSTOMA. — An oblique eared bivalve ; hinge 
destitute of teeth or internal pit ; line of the hinge straight 
in one valve, in the other deeply cut by an angular sinus.” 
— ( Sowerby.) 
1. P. Smooth, depressed, deltoid, with the posterior side round- 
ed in to the front ; ears small, anterior one longest, placed in a large broad 
and straight furrow ; beaks pointed ; surface obscurely marked with diver- 
ging striae. — Sower. Min. Conch, t. Ixvii. — In Lias. 
2. P. spinosum, — Obovate, longitudinally^ furrowed ; sides nearly equal, 
