580 THE VOYAGE OF H.M.S. CHALLENGER. 



Habitat.— Station 24, March 25, 1873 ; lat. 18° 38' 30" N., long. 65° 5' 30" W.; 

 off Culebra Island, West Indies ; depth, 390 fathoms ; bottom, Pteropod ooze. One 

 specimen ; female. Dredged. 



The carapace is nearly half the length of the animal ; it is dorsally carinated and 

 anteriorly produced to a laterally compressed and deep rostrum, that projects below the 

 level of the dorsal ridge, and is inserted deeply between the antennae. It is serrate on 

 the dorsal surface, two rather large teeth being placed posterior to the cervical fissure, 

 and the others anterior to it ; the latter gradually decrease in size and traverse the 

 margin of the rostrum to the under surface of the distal extremity. The inner and 

 the outer canthus of the orbit is furnished with a small tooth. The fronto -lateral angle 

 of the carapace is produced to a prominent point, and the lateral walls are adorned with 

 tubercles. 



The anterior two somites of the pleon are dorsally smooth, but their anterior margins 

 are elevated, so that when viewed laterally the elevations resemble teeth. The third, 

 fourth, and fifth somites are smooth and even, and the sixth is dorsally armed with two 

 rows of teeth. 



The telson (fig. 2z) is triangular and furnished with small spines on each lateral 

 margin and on the terminal extremity. 



The ophthalmopoda are short and orbicular. 



The first pair of antennae scarcely reaches beyond the apical extremity of the 

 rostrum ; the first joint of the peduncle is longer than the ophthalmopod, the second 

 and third are short and subequal. The second pair of antenna? is about as long as the 

 carapace, and carries a scaphocerite that does not reach quite to the extremity of the 

 rostrum. 



The mandibles (fig. 2d) are short and robust, and have the molar process furnished 

 with a series of small serrate teeth, and one strong conical tooth in the centre. The 

 first pair of gnathopoda (fig. 2h) is six -jointed, the last two joints being reflexed against 

 the preceding ; the basis carries a long and slender ecphysis that is three times as long 

 as the limb. 



The first pair of pereiopoda (fig. 2k) is robust and short, having the chela strong, 

 articulating with the carpos at the inferior angle ; the pollex and dactylos are tipped 

 with hairs, and a fasciculus of similar hairs tips the upper distal extremity of the carpos 

 and meros also. The second pair of pereiopoda (fig. 21) is slender and feeble ; the 

 two articuli of the carpos being each subequal in length to the palm of the propodos ; 

 the dactylos is short and stout, the pollex slender. 



The third pair of pereiopoda is also feeble, corresponds in length with that of the 

 second pair, and terminates in a short simple dactylos. The fourth and fifth pans are 

 broken off at the coxal joints. 



