SI 4. i DON AX. 



tricis plus minusve decussata, area postangulari declivi couvexa, 

 prope umbones nonnunqnam liris concentricis rugata, margine ven- 

 trali subiequaliter convexo, margine dorsali antico declivi, subexca- 

 vato. — This shell is stouter and more regularly oval than its nearest 

 allies. In most of the specimens can be traced a decussated 

 sculpture in parts from the posterior angle to the middle. In 

 I), semistriala, Poli, this character is strongly marked and covers 

 two-thirds of the shell. In the young state the postangular area 

 shows strong ridges, which disappears partially or wholly when 

 adult. 



55. In consequence of an alteration in the nomenclature and 

 synonymy of villains (Anatinum), trunculus, etc., this number is 

 omitted. Mr. Jeffreys having thoroughly investigated these 

 species, I have adopted his views. 



56. Cumingii (f. Of, 65), Bunker. — Testa oblonga, compla- 

 nata, glaberrima, albo roseo lividove radiata, postice brevi sub- 

 truncata, antico rotundo, oblongo, margine ventrali arcuato, intus 

 crenuhito. — This much resembles a flattened form of B. trunculus. 



57. nitidus (f. 75), Reeve. — Testa elongata, compressa, tenui, 

 fulvo triradiata, antice producta, prope marginein laevigata, 

 postice et medio rugis concentricis prope marginem rectiusculis 

 lirata, margine ventrali rectiusculo, intus denticulato. — This little 

 shell exhibits a sculpture at the back of the angle and along a 

 portion of the posterior and middle of the surface similar to that 

 in the young of the Mediterranean variety of B. analina, but it 

 seems too long and straight for that species. 



5S. poi.itus (f. 84, 85), Ba Costa. — Testa elongata, laevigata, 

 compressa, lutea, spadiceo variegata, post medium fascia alba 

 radiata, antice elongata, marginibus dorsali et ventrali paulo con- 

 vexo, postice subacuminatim producto, margine ventrali kevi. — 

 The young shell figured by Reeve under the name B. variegala 

 evidently belongs to this well-known species, 



59. gracilis (f. 76, 77, 7S, 79), Hani. — Testa angusta, crassa, 

 elongata, tumida, alba, lilacea, violacea, obscure fasciata, radiatim 

 tenuissirae leviter striata, margine dorsali purpureo lineata, antice 

 elongata, acuminata, margine ventrali medio convexo, intus ere- 

 nato, post medium subcontract, postice producto, obscure an- 

 gulato subacuminato. — A beautifully-formed elongated shell. 



GO. navicula (f. SO), Hani. — Testa quam D. gracilis magis 

 inflata, latiore, epidermide viridi induta, margine ventrali magis 

 convexa. — A much broader shell than D. gracilis. 



