DONAX. 307 



liter costata, costis ad angulum subundatis, interstitiis striatis, 

 area postangulari complanata, mavgine ventrali intus denticulate 

 — A remarkable three-cornered species, sculptured with diagonal 

 rib?. 



12. graxifekus (f. IS), lies//. — TestS D. semisulcata simili sed 

 tumidiore, ante angulum et ad aream postangularem minute de- 

 cussatim granosa, carina magis obtusa. — More inflated and more 

 obtuse than B. semisulcata, very finely granosely decussated, the 

 ridges being continued past the angle on the posterior area. 



13. acuminatus (f. 14), Des/i. — Testa B. semisulcata forma 

 simili, sed postice minime granoso-striata, angulo vix serrate — 

 The want of posterior sculpture alone distinguishes this from B. 

 semigranosa. 



14. meta (f. 17), Rcere. — Testa B. semigranosa simili, sed 

 magis obtusa, ad angulum semi-rotunda, vix serrata. — More 

 obtuse at the apex and posterior angle than B. semisulcata, the 

 angle not serrated nor keeled. 



15. ixtuo-eadiatus (f. 25), Reeve.- — Testa brevi, elevata, 

 cuneiformi, acute angulata, carinata, pallida, extus obscure, intus 

 valide, prope umbones purpureo trilasciata, radiatim striata, pnst- 

 angulum dense rugoso-decussata. — This shell would resemble a 

 small B. Cayennensis, but it is sharply keeled posteriorly and 

 pointed in front. The purple rays are bright within, but dull 

 without. 



1G. asper (f. 24), Hani. — Testa solida, alba vel purpurasccnti, 

 subsequalitcr trigona, antice radiatim striata, postice prope an- 

 gulum granoso-sulcata, post angulum striata, maraine postico 

 ventrali dcnticulato, area postangulari infra convexa, supra eon- 

 ca\ a, umbonibus elevatis, latere antico valde declivo. — An elevated, 

 solid species, nearly ecpually trigonal, grained near the angle. 



17. dentiferus (f. 23), Haul. — Testa elevatim trigona, rosea 

 seu purpurasccnti, radiatim striata, prope marginem anticum 

 laevigata, striis posticis magnis ad marginem dentatis, postice 

 biangulata, angulo primo elevato, angulo secundo duplicato mar- 

 gine dentato, area postica declivi, granosa, angulatim convexa. — 

 A very broad shell, with sharp, elevated angle ending in denticu- 

 lations, and a second posterior angle duplicate or ending in the 

 same way. It occurs pure white, rose, and violet. 



IS. assijiilis (f. 21), Haul. — Testa erassa, oblonga, ventri- 

 cosu, laevigata, obscure purpurea et pallide subviridi, obscure 



