(60) Neritina porcata (Gould) Hab. St. Christoval, and Faro Island, Bougainville Straits, in streams.

(61) Neritina variegata (Lesson) Hab. St. Christoval, Ugi; Simbo or Eddystone; Faro Island, Bougainville Straits; Choiseul Bay; in streams.

(62) Neritina turtoni (Récluz) Hab. A stream in the Shortland Islands; streams in Guadalcanar; imbedded in a dark calcareous loam exposed in the banks of a large stream near to its mouth at Sulagina on the north coast of St. Christoval.

(63) Neritina brevispina (Lamarck) Hab. Streams in Shortland, Treasury, and Ugi Islands. The specimens from Treasury Island were destitute of spines.

(64) Neritina squarrosa (Récluz) Hab. Streams in Treasury Island.

(65) Navicella sanguisuga (Reeve) Hab. Streams in Faro Island, Bougainville Straits.

(66) Navicella suborbicularis (Sowerby) Hab. Guadalcanar, St. Christoval, Ugi, Treasury and Faro Islands in Bougainville Straits.

(67) Unio guppyi (nov. spec.) Hab. Streams in the Shortland Islands.

(68) Cyrena, spec. Hab. In the lower parts of streams and in mangrove swamps, Choiseul Bay. Note.—This species is not referred to in the original paper.