MOLLUSCA. 63 



excavata, subacuminata, postice rotundata, lineis divaricatis striata ; marginibus ventralibus cre- 

 nulatis; cardine antice dentibus 7, postice 22-24. 



Inhab. China Sea. From eighty-four fathoms. 



A single valve only was brought up from this great depth, and presents a 

 character in its sculpture which has not hitherto been met with in any recent 

 species, but which is also found in the following. This peculiarity consists of the 

 presence of lines diverging from an angle near the middle of each valve. It how- 

 ever occurs in an English fossil, N. Cobboldice. 



256. Nucula castrensis, Hinds, 1. c. p. 98, (Plate XVIII. fig. 5.) Testa elliptica, antice rotun- 

 data, epidermide olivacea induta ; lineis divaricatis ; marginibus ventralibus crenulatis ; cardine 

 antice dentibus 5, postice 11. 



Inhab. Sitka, North-west America. A single specimen was dredged in the 

 harbour, from seven fathoms, sand. 



257. Nucula tumida, Hinds, 1. c. p. 98, (Plate XVIII. fig. 6.) Testa elliptica, tumida, striata; 

 marginibus ventralibus integerrimis : cardine antice dentibus 6, postice 15; intus laeviter striata. 



Inhab. Straits of Malacca. From seventeen fathoms, among mud. 



258. Nucula marmorea, Hinds, 1. c. p. 98, (Plate XVIII. fig. 7.) Testa elliptica, solidula, 

 albida, sulcata ; litis ad angulum planulatis ; latere antico brevi, subacuminato ; marginibus ven- 

 tralibus minute crenulatis. 



Inhab. Straits of Malacca. From seventeen fathoms, in society with 

 iV. tumida. 



259. Nucula declivis, Hinds, 1. c. p. 98, (Plate XVIII. fig. 8.) Testa parva, oblique elliptica, 

 solidula, epidermide tenui, fusca. induta; latere antico brevi; margine dorsali longe inclinato, ven- 

 tralibus crenulatis. 



Inhab. ? 



A still more oblique shell than N. pisum, to which it is closely allied. 



260. Nucula Belcheri, Hinds, 1. c. p. 98, (Plate XVIII. fig. 11.) Testa, polita, oblonga, sul- 

 cata, antice elongata, truncata, angulata; ab umbone biangulata, tertio intermedio minori ; dentibus 

 numerosis, serierum ambarum numero subsequali ; margine ventrali subrecto. 



Inhab. L'Agulhas Bank, Cape of Good Hope. Dredged from a depth of 

 forty to fifty-four fathoms. 



261. Nucula retusa, Hinds, 1. c. p. 99, (Plate XVIII. fig. 9.) Testa parva, nitida., laevigata, 

 subsequilaterali, antice retusa, subacuminata; umbonibus elevatis. 



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



N. retusa is distinguished from N. nicobarica, to which it bears some affinity, 

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

 slightly disposed to terminate in a point. 



