296 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 6 



Robulus cf. cultratus Montfort 

 Plate 37, Figs. 3, 4 



Numerous specimens, two of which are drawn, seem to belong within 

 the range of this very widely recorded species. 



Stations: 56, 60, 67, 79, 80, 1006, 1009, 1077, 1078, 1082, 1083, 

 1100, 1101, 1110, 1112, 1116, 1117, 1120, 1128, 1135, 1139, 1170, 1171, 

 1178, 1180, 1182, 1183, 1184, 1186, 1187, 1190, 1194, 1195, 1198, 1200, 

 1201, 1218, 1219, 1244, 226, 227, 2016, 2023, 2070, 2140, 2144, 2156, 

 2158, 2161, 2163, 2165, 2166, 2169, 340, 406, 413, 415, 416, 417, 452, 

 461, and 467. 



Distribution. — Stations 80 through 1244 off San Pedro and the 

 Channel Islands place this species at a depth range of 26 to 230 fms. off 

 Santa Rosa Island with an average of 68 fms. Stations off Mexico give 

 a range of 7 to 250 fms. with an average of 90 fms. At Panama, the 

 depth was 54 fms. In the Galapagos Islands, 28 to 68 fms. with an 

 average of 64 fms. The hauls off Guadalupe and Duncan Islands showed 

 the largest numbers. 



RoSulus cf. cultratus Montfort, var. 

 Plate 37, Figs. 5-8; Plate 38, Figs. 1-3 



The figured specimens show a considerable amount of variation and 

 would be placed under this species by numerous authors from a study of 

 their figures. There are many intermediate forms which make this group 

 a very confusing one. 



Stations: 82, 1055, 1069, 1079, 1083, 1101, 1103, 1105, 1117, 1169, 

 1177, 1195, 1198, and 1212. 



Distribution. — Off the Channel Islands with depth range of 45 to 

 285 fms. The average depth is 182 fms. Some of the best material was 

 off Seal Beach in 225 fms. 



Robulus orbicularis (d'Orbigny) 

 Plate 38, Figs. 4-7 



Numerous forms have been referred to this species from widely sepa- 

 rated areas. The series here figured seems to come within the range of 

 variations of this species. As so many forms have been referred to this 

 species, no attempt is made to give a synonymy here. 



