604 MR. E. A. SMITH ON SHELLS [Jutie 2, 



&c., in a marshy district in the interior of the Shortland Islands, 

 Bougainville Straits ; also from a stream in Choiseul Bay, and from 

 the vicinity of Star Harbour on the south-east coast of San 

 Christoval, "found living on the trunks of trees 300 feet ahove the sea 

 and about 150 feet above an adjacent stream. 



The majority of the specimens from the above localities are very 

 like Reeve's figure (Conch. Icon, f. Id). One specimen, however, 

 from a stream in Choiseul Bay, is worthy of special notice on 

 account of its extraordinary size. It is as large as the shell figured 

 by Gould (Wilkes's Explor. Exped. pi. xi. fig. 1H5) from Fiji, and, 

 hke it, has the edge of the columella furnished with about a dozen 

 small denticles, agreeing in this respect with N. subsulcata. The 

 portion of the specimen which equals an average-sized example is 

 quite normally painted ; but the rest or aftergrowth is mostly of a 

 sombre olive-brown, with only very faint indications of the spiral 

 mottled black zones. The operculum is quite similar to that of other 

 specimens, but much thickened with flesh-red callus on the inner 

 surface. 



The distribution of this species has already been given by Von 

 Martens in his monograph of the genus. In addition to the localities 

 there enumerated, I may mention that in the British Museum there 

 are specimens from Amboyna and the Admiralty Islands collected by 

 the Challenger Expedition ; and others from Guadalcanar, San 

 Christoval, and Ysabel Islands of the Solomon group, presented by 

 J. Macgillivray, Esq., and J. Brenchley, Esq. 



51. Neritina subsulcata, Sowerby. 



Uab. Streams in Treasury and Faro Islands, and at Choiseul 

 Bay ; also found living in numbers on the stems of tree-ferns, betel- 

 nut palms &c., in a marshy district in the interior of the Shortland 

 Islands ; also from a stream in the vicinity of Star Harbour on the 

 south-east coast of San Christoval ; from a stream in the middle of 

 the island of San Christoval 3-4 miles from the coast ; from the 

 sides of a freshwater stream, found at an elevation of 500 feet above 

 the sea at Cape Keibeck, San Christoval, and finally from a stream 

 in Ugi Islands. 



Mr. Guppy informs me that this is the most widely distributed 

 species of the genus which occurs in the Solomon group, and that 

 when first picked off the rock it ejects a watery fluid possessing a 

 powerful musky odour. 



Some of the specimens are considerably eroded, and the erosion is 

 always greatest in non-calcareous districts, where the carbonic-acid 

 gas of the rain is not previously expended as a dissolving agent of 

 limestone rocks. 



Although this species very closely approaches N. cornea, it may, 

 I think, be held distinct on account of its difference in coloration, 

 the crenulated and straighter margin of the columella, and the 

 shghtly finer sculpture on the outer surface of the operculum, 

 especially towards the outer curved margin. 



