12 WORMS. TESTACEA. 46. 47. 



Shell about 2 inches long, one and a half broad, generally" much 

 distorted and irregular on the surface, with numerous unequal 

 fine ribs, rufous, whitish, or variegated: ears sometimes large,, 

 sometimes hardly visible. 



293. P.glaber. Ears equal: shell very thin, with 15 

 faint rays, within marked with rays divided by a 

 single groove. 



Pennant Br. ZooL \\.p. 102. n. 68. 



294. F. varius. Ears* very unequal : shell with about 12 

 ribs beset with transverse prickly scales. 



Br. ZooL t. 6 1./. 64. Donov. tab. \.f. \. 



Shell about 2 inches wide, 2 and a quarter long,, variously co- 

 loured and marked, with rough spinous protuberances down the 

 rays especially towards the margin : ears very unequal,, the larger- 

 one wrinkled and armed beneath with 5-7 spines, the smaller 

 with a double row of spines, 



395. P. obsoletus. Ears unequal : shell dark purple* 

 with numerous fine longitudinal striae 8 or 10 of which 

 are more prominent. 



Br. Zool. t. 61. /. 66. Donovan, tab. \.f. 2. 



Shell hardly an inch long, dark purple with 8 obsolete darker 

 rays, smooth and brownish within, . equivalve : ears unequal, the 

 larger-one wrinkled and striate. 



296. P. Items. Ears unequal : shell flat thin, pellucid, 

 smooth except a few faint concentric ridges. 



Montague Brit. Shells. p. 150. tab. <$./. 4. 



Shttt nearly orbicular, about 6 lines long, yellowish-white, 

 purplish-brown, or chesnut, often variegated, within white with 

 the margin crenulate, sometimes striate near the margin : ears 

 strongly striate longitudinally and very finely transversely. 



46. OSTREA. Oyster. 



297. O. edulis. Suborbicular, rugged, with undulate 

 imbricate scales ; one valve flat and entire . 



Da Costa tab. \\.f. 6. Linn. Trans, vi.f. i9.f. 9. 10. 



Shell varying much in size and bulk, generally brown, with une- 

 qual valves, the upper-one flat, the lower very convex and rugged 

 'ransversely striate and often longitudinally ribbed, within pearly 

 white : beak rather oblique, with a row of small knobs running 

 down each side. 



298. O.sazatilis. Suborbicular, very thin, pellucid, a 

 little scaly : the larger-valve with strong longitu- 

 dinal ribs. 



Found adhering to rocks and stones near the low water mark 

 at the Mumbles, and differs from the last in being always very 

 thin and transparent, not so rugged, and in the lower-valve 

 being furnished with strong longitudinal ribs which often end in 

 hollow scales : Shell 2 or 3 inches long, variously shaped, but 

 generally suborbicular, oblong, or subtriangular, mostly with a 

 line purple tinge,. within glofsy white. 



47. ANOMIA. 



299. A. Ephippium. Suborbicniar, pellucid, with wrin- 

 kled undulate plaits, irregularly sinuate on the 

 margin. 



J5/. Zool. t. 62. Donov. t. 26. Da Cost. t. \\.f. 3. 



Shell 2 or 3 inches Wide, produced on one side, perlatreous With 

 various tints of green purple violet or yellow, tbe perforated 

 valve transversely striate. 



