70 ZOOLOGY OF THE VOYAGE OF THE SULPHUR. 



oblonga, tenui, lineis salientibus transversis ornata ; rostro angulato, corrugato ; valvarum margine 

 ventrali acuta, simplici. 



Inhab. New Guinea, China Sea, and Singapore. On a muddy floor, in from 

 seven to eighteen fathoms. 



293. Ne^ra Gouldiana, Hinds, 1. c. p. 77, (Plate XX. fig. 17.) Testa oblonga, fragili, hyalina, 

 ventricosa; costis duodecira radiantibus ; valvis valde inaequalibus ; rostro lineis tribus obliquis 

 elevatis. 



Inhab. New Guinea ; Bay of Manila, Philippines. In from seven to thirty 

 fathoms, sandy mud. 



The specific name is in honour of Dr. Gould, the author of the able and 

 luminous Report on the Mollusca of Massachusetts. 



294. Ne^ra casta, Hinds, 1. c. p. 77, (Plate XX. fig. 16.) Testa oblonga, fragili, hyalina, 

 ventricosa; costis numerosis radiantibus, minoribus alternantibus ; transversim subtilissime striata; 

 rostro breviusculo, parvo, lineis obliquis elevatis instructo. 



Inhab. New Guinea ; dredged from a muddy floor in seven fathoms. 



295. Ne^ra didyma, Hinds, 1. c. p. 78, (Plate XX. fig. 19.) Testa oblonga, laevigata, alba ; 

 costis duabus radiantibus ; margine dorsali antica, prominula ; rostro lato, subtruncato. 



Inhab. The west coast of Veragua, in twenty-six fathoms, mud ; in society 

 with N. costata. 



On the anterior and ventral margin there is a disposition to the formation of 

 a number of small ribs ; the shell is otherwise smooth and left to the occupation 

 of the two prominent ribs, which eminently distinguish it. 



296. Nesra rosea, Hinds, 1. c. p. 78, (Plate XX. fig. 20.) Testa oblonga, albida, epiderruide 

 tenui striata induta ; valvis inasqualibus, dextra majori ; rostro attenuato, roseo. 



Inhab. New Guinea, in seven fathoms, mud. 



Not unlike diminutive specimens of N. cuspidata ; the anterior portion of the 

 shell, however, does not occupy more than a third of its entire length ; the beak 

 is more attenuated and of a rose-colour ; and I cannot perceive any vestige of the 

 angular line which extends posteriorly from the umbo. 



Family — Mactrace^;. 



Pythina. Hinds. 



Testa transversa, subasquilateralis, sequivalvis. Valva altera dente unico mediano parvo, 

 duabus lateralibus, altera dentibus duabus lateralibus. Ligamentum internum. Impressiones 

 musculares duae, rotundatae. Impressio pallii rectiuscula, sinu nullo. 



