WORMS. TESTACEA. 48. Mytitus. 163 



300. A. Sguamula. Sub orbicular, thin, membranaceous, 

 like the scale of a fish, entire, the Hat valve trans- 

 versely wrinkled. 



Walker min. Shells./. 80. Adams microsc. t. 14.7. 42. 



Shell about half an inch wide, whitish, within silvery or tinged 

 with green : beak prominent, pointed. 



301. A. aculeata. Suborbicular, thin, longitudinally stri- 

 ate, rough with small concave obtuse spines 



Montague Brit. Shells. p. 157. tab. 4.7". 5. 



Sliftl about 4 lines wide, dirty-white ; with interrupted longitu- 

 dinal striae : beak smooth,, recurved. 



302. A. undulata. Suborbicular, pellucid, with fine irre- 

 gular undulate longitudinal smooth sfriae, crossing 

 transverse curved ones. 



Donovan t. 45. Da Costa t* \ i ../. 4. Gstrca. 



Shell an inch or rather more wide, whitish, within perlaceous 

 or greenish, mostly undulate on the margin, sometimes finely 

 striate transversely : beak small, pointed : aperture large, oval, 



303. A. cymbifonnis. Oblong, coarse, slightly striate, 

 with the beak, incurved, perforated on the flatter 

 valve. 



Linn. Trans, viii.jft. 104. tali. 3-/. 6. 



Shell 5 eighths of an inch long, 3 eighths broad, whitish, very- 

 tender. 



48. MYTILUS. MusselL 



304. M. etlulvs. Oblong-oval* nearly smooth, pointed and 

 slightly carinate at the beak, truncate and a little 

 curved on one side. 



Br. Zool. t. 63, /. 73. Donovan t , \ 28. Da Costa fi 15. /.. 5. 



Shell about 3 inches long, half a one broad, blackish blue covered 

 with a brown or yellowish skin, sometimes radiate with bluer- 

 rounded at the bottom, within white in the middle, blue about the 

 margin. 



305. M. incnrvatus* Oblong-oval, nearly smooth, much 

 curved on one side under the hinge, beneath broad 

 and produced on the same side. 



Br. Zool. t. 6 4 ./. 74. Lister Conch, t. 337 ./. 195. 196. 



Shell resembling the last, except that it is less, the beak is more 

 truncate ; under which on one side it is very crooked and then 

 greatly dilated, covered with a thick rough skin, vrithin 

 violet. 



306. M. pellucidus. Oval, smooth, open, pellucid, whitish 

 or blackish radiate with deep blue or purple. 



Br* Zool. t. 63. f. 75. Donovan tab. 81. 



Shell 2 inches long, one wide, a little gibbous on one side, co- 

 vered with a yellow skin, within blueish-white radiate with blue. 



307. M. barbaius. Oval-oblong,, roughish, thin, obtuse 

 at the beak, ferruginous-yellow, obliquely clothed 

 with a thick beard on the lower-part. 



Br. Zool. t. 6^,f, 76. A. Donovan t, 70.. 



Shell about 2 inches long, one wide, short, ventricose, the 

 posterior side rising a little above the beak, within white, 

 clothed in an oblique manner with a thick beard on the lower 

 half: beak without crepuJations withio, Probably the young shell 

 of M, Modiolus. 



