23 

 STATION 258. Tual anchorage, Kei Islands. 22 meters. Lithothamnion, sand and coral. Isis hippuris. 



STATION 273. Anchorage off Pulu Jedan, East coast of Aru Islands. 13 meters. Sand and shells. 

 Isis reticulata. 



STATION 279. Ruma-Kuda Bay, -Roma Island. 36 meters. Mud and sand. Isis hippuris. 



STATION 300. io48'.6S., 123 23'.! E. 918 meters. Fine grey mud. Peltastisis cornuta. 



STATION 301. io38'S., I2325'.2E. 22 meters. Mud, coral and Lithothamnion. Isis hippuris. 



STATION 303. Haingsisi, Samau Islands. Up to 36 meters. Lithothamnion. Isis hippuris. 



It appears from the above list that Isidce were collected at 26 stations during the 

 Siboga Expedition. By far the most widely spread of the species collected, so far as the territory 

 covered by the Siboga is concerned, is Isis hippuris, which was secured from 9 stations, over 

 one third of the total number. It is a somewhat remarkable fact that in only two cases (one of 

 which is uncertain) were more than a single species taken from one station; while no station 

 yielded more than two species of Isida. Contrasted with the 17 species of Muriceida from 

 Station 310, this seems a decidedly pour showing. 



The genus Isis is the only one that can be regarded as comprising distinctly shallow 

 water forms, its range being from 22 to 45 meters. All of the other genera are truly inhabitants 

 of the deep water, the bathymetric distribution of the Siboga material being as follows: 



Ceratoisis, 595 to 1264 meters; Acanella, 450 to 1570 meters; Mopsea, 80 to 469 meters; 

 Peltastisis, 827 to 918 meters. 



