470 Zoological Society, 



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

 preceding. 

 Cab. Cuming. 



NucuLA RETUSA. Nuc. testd pavvd, nitidd, lavigatd, suhcBquilate- 

 rali, antice retusd, suhacuminatd ; umbonihus elevatis. Long. 2J ; 

 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 slight 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, — N. tenella by its flattened shape, smooth polished surface, and 

 by being lengthened and rounded anteriorly,— and JV. retusa by being 

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

 slightly disposed to terminate in a point. 



NucuLA CRASSA. Nuc. tcstd oblougd, ventricosd, crassd, sulcatd, 

 antice arcuate rostratd, excavate angulatd; liris rotundatis ; postic^ 

 valde rotundatd; intus pallide luted. Long. 14 ; lat. 6 ; alt. 10 Iin» 



Hab. Australia. 



Cab. Cuming. 



NxJCULA liATA. Nuc. testd oblong d, politd, planulatd, lineis impressis 

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

 gine dor salt anticd 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-BLATA. Nuc. tcstd luteo^virente, oblongd, argute sulcatd ; 

 antice arcuate rostratd, sulcis paululiim obliteratis ; umbonibus 

 prominuUs. 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. ;7e//fl, and presenting 

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



NucuLA VENTRicosA. Nuc. tcstd oUongd, pallide luted, ventricosd, 

 sulcatd ; anticl subrecfh 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 difi'erent to that of the 



