112 University of California Publications in Zoology [Vou. 23 
Genus Calastacus Faxon 
Carapace subcylindrical, back arched, dorsally carinate; cervical groove dis- 
tinct. Eyes almost or quite without pigment. Antennal ‘‘thorns’’ both of good 
size. Exopodite of uropods with a suture. 
Key TO THE CALIFORNIA SPECIES OF CALASTACUS 
I. Carapace granulate; no spines behind those at the base of rostrum. (Known 
only from 345 + fathoms.) ops irate ats TE 
] . —e 
II. Carapace not granulate; five rows of spines behind the rostrum. (Known 
only from 200 + fathoms.) ; : 
quinqueseriatus, p. 113. 
Calastacus investigatoris Anderson 
Calastacus investigatoris Anderson, Jour. Asiatic Soc. Bengal, 65, pt. 2, 
p. 97, 1896; Illus. Zool. ‘‘Investigator,’’ Crust., pt. 4, pl. 25, fig. 1, 
1896; Aleock, Deser. Cat. Indian Deep Sea Crust. Dee. Macr. Anom. 
Indian Mus., p. 191, 1901; Rathbun, H. A. E., 10, 151, 1904. 
Fig. 75. Calastacus investigatoris; a, dorsal view; 6, lateral view (after 
Alcock). 
Characters.—Carapace (rostrum included), measured in the middle line, as 
long as the first five and a half abdominal somites; surface studded with sharpish, 
vesiculous granules; finely carinated in the middle line, carina terminating in a 
vesiculous tubercle and having a similar tubercle in the middle of its gastric 
course; cervical and branchial grooves very conspicuous. Rostrum not quite 
reaching end of second joint of antennular peduncle, its sides prolonged onto the 
gastric region as two sharp ridges, each of which carries two spines. In the 
