CONCHOLOGY. 



93 



Glauca. 



1. Solida. Shell strong, sub-triangular, of a yellow- 

 ish-white colour, with a few concentric ridges ; sides 

 nearly equal ; lateral teeth large, prominent, crenated 

 within ; length an inch and a half, breadth an inch and 

 three quarters. 



Brit. Zool. tab. 52. fig. 43. 

 Brit. Sheik, tab. 61. 

 A common shell on all the coasts. 



2. Truncata. Shell triangular, strong, thick, and 

 nearly smooth; umbo central, large, and very promi- 

 nent ; sides equal, much flattened, and truncated ; the 

 front margin rounded; length an inch and a half, 

 breadth an inch and three quarters. 



Brit. Shells, tab. 126. M. subtruncata. 

 Common on all the coasts. 



3. Subtruncata. Shell strong, sub-triangular, trans- 

 versely striated, rounded on one side, the other more 

 pointed and longer; umbo large and prominent, the 

 sides near the beak much turned inwards, especially 

 the anterior, winch is depressed into a cordiform shape 

 when the whole shell is viewed sidewise; length three 

 quarters of an inch, breadth an inch. 



Test. Brit. tab. 27. fig. 1. 

 Brit. Zool. tab. 52. fig. 42. M. stultorum. 

 Equally common with the preceding species. 



4. Stultorum. Shell thin, sub-triangular, semi-pellu- 

 cid, faintly striated transversely, irregularly rayed lon- 

 gitudinally with broad and narrow whitish lines; umbo 

 central, prominent, sides nearly equal ; length an inch 

 and three quarters, breadth two inches and a quarter. 



Brit. Zool. tab. 49. fig. 30. Tellina radiata. 

 Common on all the British shores. 



5. Cinerea. Shell thin, sub-triangular, truncated, and 

 of a cinereous colour ; beak large and very prominent, 

 slightly turned to one side, beneath which there is a de- 

 pression ; opposite side much compressed laterally ; in- 

 side pale, with a tinge of blush. 



Test. Brit. p. 35. 

 Found by Mr Bryer on the coast at Weymouth. 



6. Dealbata. Shell thin, fragile, pellucid, oval, white, 

 very finely striated, with a few coarser concentric wrin- 

 kles; the smaller end gaping a little ; umbo nearest the 

 larger end ; middle tooth in one valve broad, bifurca- 

 ted, angulated close to the beak ; lateral teeth not very 

 remote; inside glossy white, moderately concave; mar- 

 gin plain, with a sharp edge ; length an inch, breadth 

 an inch and a half. 



Test. Brit. tab. 5. fig. 1. 

 First noticed as British by Dr Pulteney, who recei- 

 ved it from Mr Bryer at Weymouth. 



7. Triangularis. Shell white, opake, strong, sub-tri- 

 angular; beak prominent, obtuse; sides a little unequal; 

 hinge strong, primary teeth in one valve large bifid, in 

 the other two small teeth, with a triangular cavity be- 

 tween ; lateral teeth depressed ; margin strongly crena- 

 ted ; length one-eighth of an inch, breadth rather less. 



Test. Brit. tab. 3. fig. 5. 

 Found by Mr Montagu in Falmouth harbour, and on 

 the coast of Devon. 



8. Minutissima. Shell white, nearly smooth, sub-tri- 

 angular; umbo prominent; inside smooth, margin 

 plain ; hinge strong ; primary teeth in one valve two, 

 separated by a cavity for the reception of a single large 

 tooth in the opposite valve. 



Test. Brit. p. 37. 

 Found by Mr Montagu on a new species of coralline, 

 in company with Peclen fragilis. 



9. Glauca. Shell oval, of a dirty white colour, very 

 finely striated transversely, and marked with broad and 

 narrow glaucous rays ; the anterior end wrinkled ; the 



beaks reflect backwards, with a narrow gape between Bivalves. 

 them ; length two inches and a half, breadth three inch- """"Y"""'' 

 es and a half. 



Brit. Shells, tab. 125. 

 Found by Miss Pocock on Hale sands, under Le- 

 lant, Cornwall. 



Genus XXXV. Lutraria. 



Shell transverse, inequivalved, gaping at the exlremi- XXXV. 

 ties ; ttvo oblique diverging hinge teeth accompany a large Lutraria. 

 pit for the reception of the ligament ; no lateral teeth. 



1. Vulgaris. Shell oblong-oval, gaping a little at vulgaris, 

 both ends, yellowish-white, with irregular concentric 



striae; umbo small, placed near to one side, from which 

 the shell slopes a little ; tooth in one valve triangular ; 

 length two inches and a half, breadth five inches. 

 Brit. Shells, tab. 58. Mactra lutraria. 

 Common on many parts of the coast, especially at the 

 influx of rivers. 



2. Hians. Shell strong, rugose, oblong, with con- Hians, 

 centric wrinkles ; umbo small, margin next to the hinge 

 sub-arcuated ; inside white, with a strong elevated ridge 

 along the upper side of the cicatrix ; the longer end 

 with a considerable gape; length two inches and a quar- 

 ter, breadth five inches. 



Brit. Shells, tab. 140. Mactra hians. 

 Frequent on the English coast. 



Genus XXXVI. Donax. 



Shell cquivalved, inequilateral, anterior margin, obtuse; XXXVI. 

 the hinge teeth two, either in one or both valves; the late- Donax. 

 ral tect/i one or ttvo, rather distant. 



1. Truncidus. Shell oblong, smooth, glossy, finely Truuculus, 

 striated longitudinally, covered with a thin epidermis ; 



umbo small, placed nearest to the lesser end ; margin 

 crenated; length five-eighths of an inch, breadth an 

 inch and a half. 



Brit. Zool. tab. 55. fig. 45. 



Brit. Shells, tab. 2.9. fig. 1. 

 On most of the sandy British shores. 



2. Denliculala. Shell strong, thick, sub-cuneiform, Denticula- 

 striated longitudinally; the interstices punctated; large ta, 



end much sloped and truncated, with a prominent ridge 

 upon the angle of the slope ; hinge with strong teeth ; 

 margin denticulated; length about six-eighths of an 

 inch, breadth an inch. 



Brit. Zool. tab. 55. fig. 46. 



Brit. Shells, tab. 24. D. crenulata. 

 A rare British species, said to be found by Dr Pul- 

 teney and by Mr Breyer at Weymouth. 



3. Complanata. Shell oblong, smooth, and glossy, of Coraplan*. 

 a light yellow or faint purplish colour, with spots or ta, 

 streaks of white, and one broad ray from the beak to 



the margin ; umbo placed nearest to one end ; teeth 

 small, margin plain; length five^-eighths of an inch, 

 breadth an inch and a quarter. 

 Test. Brit. tab. 5. fig. 4. 

 Found by Mr Montagu on the coast of Devon. It 

 likewise inhabits the Cornwall and Dorset coasts. 



4. Plebeia. Shell thick, strong, oblong, sub-oval, of piekeia 

 a dull horn colour, smooth and glossy, generally marked 



with two brown stripes longitudinally from the beak, 

 which is placed nearest to one side; margin plain; 

 length aboiit half an inch, breadth three quarters. 

 Test. Brit. tab. 5. fig. 2. 

 First found at Weymouth by the Duchess of Port- 

 land, and since at the same place by Mr Bryer. Also 

 at Dunbar by Mr Laskey. 



