146 WORMS. TESTACEA. 36. Mya. 



174. Ph. striata. Somewhat conic, strongly reticulate on 

 the upper part, irregularly striate oif the lower. 



Donovan's Shells t. 117. Chemn. Conch. 8. t. 102. /. 864-866. 



Shell half an inch long, 3 quarters broad, white, the striae here 

 and there decussate, the part about the hinge i'mooth, the lower-end 

 gaping ; tooth long, slender, much curved* 



B. Bivalves. 

 36. MY A. 



175. M. Glycemeris. Oblong-oval, coarse, lamellar, with 

 transverse wrinkled stria?, gaping at both ends, 

 obliquely truncate before and behind the beak : pri- 

 mary tooth of the hinge very thick. 



Donovan t. 143. Lister t. 414. y. 258. 



Shelf 5 inches long, 8 or 9 broad, grey or ochraceous, with an ir- 

 regular margin : beak nearly central, slightly indented both sides : 

 hinge with a lesser tooth and a feries of wrinkles. 



176. M. truncata. Suboval, truncate and much gaping at 

 the smaller end : tooUi broad, thick, very obtuse, 

 projecting, erect. 



Br. Zool. t. 41. f. 14. Donovan t. 92. Da, Cost. t. 16. f. i. 



Shell 2 inches and a half long, 3 arid a half wide, covered with a 

 yellowish skin, white under the skin, marked with concentric 

 wrinkles. 



177. M. arenaria. Oval, rounded behind: tooth broad, 

 thick, very obtuse, projecting, erect, with a small 

 lateral-one. 



Donovan t. 85. Br. Zoo/., iv. t. 42. 



Shell 2 inches and a half long, 3 wide, covered with a brown skin, 

 concentrically wrinkled : refembles the Jast, except in not being 

 truncate at the gaping end ; tooth with a projection near the bafe. 



178. M. margaritifera. Oblong, slightly kidney-shaped, 

 decorticated near the hinge, with a single tooth in 

 one valve locking into a forked one in the other. 



Donovan t. 73. Br. ZcoL t. 43. Da Costa t. 15. /, 3. 



Shell 2 inches long, ,5 broad, a little contracted in the middle at 

 the thinner end, thick, covered with a black skin which is worn 

 oft on the protuberant parts near the hinge, transverfely wrinkled, 

 pearly. greenish within; teeth strong. 



179. M. Pictontm. Oval, in each valve a broad crenate 

 tooth, with 2 lateral laminae in one valve, and one in 

 the opposite locking into each other. 



Donovan t. 89. Brit. Zool. tab. 43. /. 17. 



.Shell nearly 2 inches long, and 4 broad, dull green, nearly black 

 at the fmaller end, concentrically wrinkled, pearly within : beak 

 near the larger end. 



180. M. ovalis. Oval-oblong, rounded at both ends: 

 teeth crenate, a single one and lateral lamina in one 

 valve, and a forked one and 2 laminae in the other 



Donovan t. 174. Chemn, Conch. 6. t. i.y/6. 



Shell an inch long, nearly 2 wide, olive-green, concentrically 

 wrinkled, a little indented in front, pearly within : beak near one 

 end : hinge nearly straight. 



181. M. dubia. Oval, thin, brittle, gaping, light rufous, 

 with the rudiment of a tooth in one valve projecting 

 inwards. 



