193 WORMS. TESTACEA. 63. Dentalium. 



585. p Rotula. White, opake, flat, round, with a re- 

 gularly toothed margin. 



Kanm. and Adams Microsc. p. 63,5. t. 14.7. 9. P. Rota. 

 Found at Sandwich : very minute and rare. 



E. With the crown perforated. 



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

 on the fore-part : crown a little recurved. 



cf ??(' ';r 90 '/' 152 ' Don V ' ' 3 ' f' 2 ' Da C Sta f ' l '/ 4- 

 o/W/halfan inch long, 3 eighths wide, conic,. b.rown or white, 



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



side half way to the crown. 



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

 nate on the margin within. 



r. Zoo/, t. 89.7. 153. Donou. t. 21 ./. 3, Da Costa t. \.f. 3, 

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

 aquaiter high, dull brown, within white or radiate with dull pur:- 

 ple, fomewhat tubercled by the crossing of the tranfverfe striae : 

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

 foration. 



588. P. Aperlura. Subconic, white, strongly ribbed 

 longitudinally with a few transverse ridges: crown 

 recurved. 



Montague Brit. Shells, p. 492. tab. 13.7. 10. 



Shell hardly a quarter of an inch long, not an eighth high, glos.'y 

 white within, with strong longitudinal tubercled ribs crofsed by a 

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

 oval, crcnulate. 



63. DENTALIUM. Tooth-shell. 



589. D. Dentalis W r hite, slightly curved, interrupted, 

 with about 20 stria*. 



fumph, mus. t. 41. /. 6. Born. mus. t. i8./. 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, fomethnes tipt with red. 



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

 smooth, continued. 



Br. Zool. t. 90.7. 154. Bonov. t. 48. Da Costa t. 2.7. to. 



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

 smooth or very minutely striate, with a few circular annulations, 

 truncate at tha tip. 



591. D. Gailus. White, glossy> smopth, slightly curved, 

 inflated near the larger end. 



Montague Brit. Shells, p. 496. tab. \$.f. 7. 



Shell hardly 3 eighths pf an inch long, nearly straight, contracted 

 at the larger end, with a rather sharp point. 



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

 curved, with 8 angles, and as many ribs. 



Donovan Brit. Shells, v. tab. 162. 



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



the larger aperture angular, and the snialler-one very narrow and 



orbicular. 



593. D. imperforatum. Whitish, slightly curved, cylin- 

 drical, transversely striate, truncate 



At tbe wilier eud 



