198 WORMS. TESTACEA. 63. Dentah'um. 



5 &5. P noiula. White, opake, flat, round, with a re- 

 gularly toothed margin. 



Knntn. and Adams Microsc. p. 635. t. 14./. 9. P. Rota. 

 ■Found at Sandwich : very minute and rare. 



E. With the crovcn perforated. 



586. P. Fissura. Oval, reticulate, cloven half way up 

 ^on the fore-part : crown a little recurved. 



\? ooL U 9°'f' , 5 2 - Donov. t. 3. /. 2. Da Coita t. \.f. 4. 



shell half an inch long, 3 eighths wide^ conic, brown or white, 

 within white or fresh-colour : margin crenate, with a slit on one 

 side half way to the crown. 



587. P.grceca. Oval, convex, strongly reticulate, cre- 

 nate on the margin within. 



Br. Zool, t.Sg.f. 153. Donov. 1. 21./. 3. Da Costa t. 1./. 3, 

 Shell about 3 quarters of an inch long, hardly half an inch wide, 

 a quaiter high, dull brown, within white or radiate with dull pun- 

 pie', fomewhat tubercled by the crossing of the tranfverfe striae : 

 margin indented : crown not central, truncate, with an oblong per- 

 foration. 



088. P. Apeiturtt. Subeonic, white, strongly ribbed 

 longitudinally with a few transverse ridges : crown 

 recurved. 



Montague Brit. Shells, p. 492-. tab. 13./. 10. 



Shell hardly a quarter -of an inch long, not an eighth high, glossy 

 white within, with strong longitudinal tubercled ribs crofsed by a 

 few ridges: crown reflected, with a rhombic perforation: margin 

 oval, crenulate. 



63. DENTALIUM. Tooth-shell. 



589. D. Bentalis White, slightly curved, interrupted, 

 with about 20 striae. 



Bumph.mus, t. 41. f. 6. Born.mus. t. i8.y. 13. 



Shell about half an inch long, tapering to a fine point, pervious,, 

 closely striate, with sometimes a few faint- annulations at the 

 larger end, opake white, fometimes tipt with red. 



590. D. Mntalis. White or yellowish, slightly curved, 

 smooth, continued. 



Br. Zool. t. go./. 154. Donov. t. 48. Da Costa t. 2./. io. 



Shell an inch and a half long, tapering to a fmall point, pervious, 

 smooth. or very minutely striate, with a few circular ambulations, 

 truncate at the tip, 



5D1 . D. Gadus, White* glossy, smooth, slightly curved, 

 ! inflated near the larger end. 



Montague Brit. Shells. p % 496. tab. t$.f. 7. 



Shell hardly 3 eighths^of an inch long, nearly straight, contracted. 

 atthelargerend, with a rather sharp point. 



592. D. slriatulum. Green tipt with white, slightly 

 curved, with 8 angles, and as many tffb's. 



Donovan Brit. Shells, v. tab. 162. 



Shell about an inch and a half long, sometimes grey-white, with 



the larger aperture angular, and the anvaller-ohe very narrow and 



orbicular. 



593. B.imperforatum. Whitfeh, slightly curved* cylin- 

 drical, transversely striate, truncate and ifttpetforate 

 at 4he smaller end. 



