WORMS. TESTACEA. 40. Mactra. 155 



finely striate, with a few coarser wrinkles, gaping a 

 little at the smaller end. 



Montague Brit. Shells, p. 95. tab. 5./. 1. 



Shell an inch long, an inch and a half broad, a little produced at 

 one end, with a sharp plain margin : beak rather oblique : middle- 

 tooth in one valve broad, forked, angulai>clofe to the beak. 



243. M. compressa. Suboval, subtriangular, thin, flat, 

 semipellucid, irregularly wrinkled : in one valve a 

 single tooth locking into a Cloven one in the other. 



Donovan t. 64, f. 1. Tellina plana. Da Cost. t. 13./. 1. 



Shell an inch and a half long, 2 broad, yellowish-white, or pale 

 ferruginous, often with dark bands: beak fin all, central: hinge 

 without lateral teeth : cavity at the cartilage large, triangular. 



244. M. BoysiL Oval, flat, thin, pellucid, glossy-white, 

 nearly smooth : beak oblique, a little turned. 



Montague, t. 3./. 7. Linn. Trans, iv.i. i6.y". g-12. 



Shell half an inch long, 3 quarters broad, with fometimes a few 

 obfcure striae : teeth one in each valve, with a broad lateral tooth 

 in one valve only : cartilage thin, long. 



245. M. triangularis, Subtriangular, opake, white, 

 smooth : hinge with a large cloven tooth in one valve, 

 in the other two small ones with a triangular cavity 

 between them. 



Montague Brit. Shells, p. 99. tab. 3./. 5. 



Shell 3 lines broad, 2 long, a little produced on one side, strongly 

 crenate on the margin within. 



246. M. lutraria. Oblong-oval, nearly smooth: hinge 

 without lateral teeth, in one valve a small and large 

 triangular cavity, in the other a cavity and raised tri- 

 angular tooth. 



Br. Zool. t. 52. y. 44. Donovan t. 58. Linn. Tr. vi. t. 16. f. 3. 4. 



Shell above 2 inches long, 4 broad, yellowish-white with pale 

 bands, fometimes with a few striae, gaping a little at both ends, 

 glossy-white within : beak fmall, nearer the larger end. 



247. M. glauca. Oval, finely striate, wrinkled at the an- 

 terior end, dirty-white, with broad and narrow brown- 

 ish or glaucous rays. 



Donovan Brit, Shells t. 125. Chemn. vi. t. 23./. 232, 233. 



Shell 2 inches and a half long, 3 and a half broad : beaks turned 

 backward, with a narrow gape between them. 



248. M. tenuis. Subtriangular, equilateral, thin, semi- 

 pellucid, white, wrinkled : hinge with a forked tooth 

 in one valve and a simple one in the other, with late- 

 ral teeth in each. 



Montague. Brit. Shells, app.p. 572. 



Shell a quarter of an inch long, rather more broad: beak fmall, 

 central, produced, straight. 



249. M. hians. Oblong, strong, rugged, gaping at the 

 smaller end, arched under the beak : beak near the 

 larger end. 



Donovan t. 140. Linn, trans, vi. t. \6.f. 5. t5. 



Shell 2 inches and a quarter long, 5 broad, opake, dark-brown or 

 grey with often a rufous tinge, very rugged near the open end : 

 hinge with a flattish tooth, grooved on the fore-part, locking be- 

 tween two in the other valve, one of which is cloven. 



