470 Zoological Society. 



Hah. Singapore ; from seven fathoms, mud. In society with the 

 preceding. 

 Cab, Cuming, 



NucuLA RETUSA, Nuc. testd pavvd, nitidd, Icevigatd, subcequilate- 

 rali, antice retusd, subacuminatd ; umbonibus elevatis. Long. 2^ ; 

 lat, 1 ; alt. 1| lin. 



Hab. St. Nicholas, Philippine Islands ; Straits of Macassar. 



Cab. Cuming et Belcher. 



If the Lamarckian species, N. nicobarica, — a transversely elon- 

 gated, finely striated shell, with both extremities rounded and length- 

 ened anteriorly — is taken as a type of departure for the four prece- 

 ding species, then N. Belcheri will be distinguished by its great 

 transverse length, polished sulcated surface, angulated lines, trun- 

 cated extremity, and three shght projections at the termination of 

 the angles, — N. serotina by its polished sulcated surface, lengthened 

 and rounded anterior extremity, and slightly prominent dorsal mar- 

 gin, — A'^. tenella by its flattened shape, smooth polished surface, and 

 by being lengthened and rounded anteriorly, — and A', retusa by being 

 nearly equilateral, smooth, polished, and with the anterior portion 

 slightly disposed to terminate in a point. 



NucuLA CRASSA. Nuc. testd oblongd, ventricosd, crassd, sulcatd, 

 antice arcuate rostratd, excavate angulatd; liris rotundatis ; postice 

 valde rotundatd ; intus pallide luted. Long. 14 ; lat, 6 ; alt, 10 lin. 



Hab. Australia. 



Cab. Cuming. 



NucuLA LATA. Nuc. tcstd oUongd, politd, planulatd, Uneis impressis 

 excavatd ; antice elongatd, late rostratd, postice rotundatd ; mar-, 

 gine dorsali untied prominuld ; umbonibus parvis. Long, 8 ; lat, 2 ; 

 alt. 4 lin. 



Hab. New Guinea ; in from five to twenty-three fathoms, among 

 mud. 



Cab. Belcher. 



NucuLA c^LATA. Nuc. tcstd luteo-virentc, oblongd, argute sulcatd; 

 antice arcuate rostratd, sulcis paululilm obliteratis ; umbonibus 

 prominulis. Long. 7 ; lat. 3 ; alt. 4 lin. 

 Hab. California, between 38° 18' and 34° 24' north latitude; 

 namely, at Russian Bodegas, San Francisco, and Santa Barbara, in 

 from six to ten fathoms. 

 Cab. Belcher. 



More ventricose and acutely beaked than N. pella, and presenting 

 a partial obliteration of the sulci near the anterior dorsal margin. 



NucuLA vENTRicosA. Nuc. tcstd oblongu, pallide luted, ventricosd, 

 sulcatd; antice subrecte rostratd, umbonibus magnis, prominenti- 

 bus ; margine ventrali antice coarctatd. Long. 7 ; lat. 3^ ; alt. 

 5 lin. 



Hab. Straits of Malacca ; from seventeen fathoms, mud. 



Cab. Belcher. 



The character of the sulcation here is very different to that of the 



