150 RATHBUN 



duncle extends to the middle of the penultimate joint of the antennal 

 peduncle. The outer flagellum is almost as long as the carapace and 

 rostrum ; the inner is a fifth longer than the outer. The scaphocerite 

 projects as far as the middle of the second antennular segment, while 

 the stylocerite projects to the end of the penultimate joint of the anten- 

 nal peduncle ; this joint is nearly 3 times as long as the last joint. The 

 flagellum is broken off, but the part remaining reaches beyond the anten- 

 nular flagella. 



The outer maxillipeds reach the end of the antennal peduncle. The 

 first pair of chelipeds are missing. The second pair are rather narrow ; 

 the merus has 3 spines on its lower margin ; the carpus is half as long as 

 the merus and three fourths as long as the propodus ; palm and fingers 

 subequal ; lower margin of merus, carpus, and propodus fringed with long 

 hair. The third to fifth pairs of feet are slender ; the lower margin of the 

 distal half of the propodi is fringed with long hair; the dactyli are 

 slender, those of the third and fourth pairs contained 3 times in their 

 propodi, those of the fifth pair contained 4 times in their propodi. 



The abdomen is smooth above, but the pleura are sculptured and 

 pubescent; the telson is elongate, subquadrilateral, lateral margins 

 spinulous, dorsal surface with a few spines ; caudal swimmerets about as 

 long and as broad as the telson; inner one with two outer marginal 

 spines, carina spinulous ; outer branch with serrate outer margin, outer 

 carina with i or 2 spinules, obliquely transverse suture bordered by slender 

 spinules. 



Dimensions. In the unique type, a female, the length of the carapace 

 and rostrum along the median line is 19.6 mm., length of rostrum 3.5 

 mm., of abdomen 31.5 mm. 



Type locality. Oft Bodega Head, California, 62 fathoms (Albatross 

 station 3172). 



From the other species on the west coast of North America, viz., Axius 

 crista-galli Faxon and A. acutifrons (Bate), both of which occur off Pana- 

 ma, A. spinulicauda is readily distinguished by the five gastric carinse and 

 the black eyes. 



Genus Calastacus Faxon. 



KEY TO THE SPECIES OF CALASTACUS. 



A. Carapace granulate ; no spines behind those at base of rostrum, 



investigatoris. 

 A 7 . Carapace not granulate ; 5 rows of spines behind the rostrum, 



quinqueseriatus. 



