150 



STALK-EYED CRUSTACEA. 



curves uijward, defining the upper limit of the branchial region, and is 

 fmallj lost just before reaching the hind margin of the carapace. The 

 anterior part of this carina is separated from the orbital spine and the he- 

 patic area by a deep groove ; below this carina there is a deep vertical inden- 

 tation on the side of the carapace between the hepatic and branchial areas^ as 

 in all the species of this genus in which the middle lateral carina is obsolete. 

 The inferior lateral carina extends from the branchiostegal spine, with 

 which it is continuous, backward, pursuing a more nearly horizontal courwc 



than the upper one, and stops before reaching the hind border of the 

 carapace. 



The third abdominal segment is keeled alono; the median dorsal line. Its 



hinder half is sharply bent down at angle of about 90°, forming a prominent 

 knee. There are no median teeth on this or any of the other abdominal 

 segments. The end of the telson is acutely triangular, and is armed with 

 three pairs of articulated spines; the intermediate pair of these spines are 

 much the stoutest and longest. The dorsal face of the telson is armed with 

 four pairs of spines articulated at their bases. 



The two flagella of the antennule are subequal, and about as long as the 

 whole body minus the rostrum. The basal segment of the antennule is 

 armed externally with a spine whose acute tip reaches forward to the middle 

 of the second segment of the peduncle. The antenna with its llagellum is 

 about twice as long as the body (rostrum included) ; the scale is one half the 

 length of the rostrum, its sides convex, its external spine subterminal. 



The right carpus of the second pair of legs is composed of nine or ten 

 segments, the left of twenty-two to twenty-four. The merus of the left 

 leg of the second pair is also obscurely divided up into many (nine or ten) 

 secondary segments or annuli, as in other species of this genus. 



The last pair of abdominal appendages are about as long as the telson, 

 the outer branch being slightly longer than the inner. 



Length, 110 mm.; rostrum, 26 mm.; carapace with rostrum, 55 mm.; 

 antenna, 219 mm.; antennal scale, 14 mm. ; telson, 17 mm. 



This species was taken at four stations in the Gulf of Panama, viz : 

 Station 3385. 286 fathoms. 49 specimens {" a peck rejected"). 



a 



f 



; 



iC 



3386.' 242 

 3389. 210 

 3396. 259 



a 



6C 



U 



91 " 



7 

 18 + 50 juv. 



t 



I 



y 



Ileterocarpus vicarks is closely related to //. gillosus Bate, described from 



