900 



THE VOYAGE OF H.M.S. CHALLENGER. 



margins of the fourth and fifth somites, while the anterior show no evidence of their 

 presence, but the ventral surface in the median line of each somite is inferiorly lobed, 

 and a mass of neural substance appears to be lodged in each. The sixth pair of pleopoda 

 is unequally biramose, and extends beyond the telson for half its length. 



Eretmocaris corniger, n. sp. (PL CXLV. fig. 4). 



Carapace one-fourth the length of the animal, dorsally armed with a strong tooth 

 on the gastric region, anteriorly produced to a rostrum, which is broken short off in this 

 the only specimen obtained. 



Pleon having a horndike tooth on the dorsal surface of the third somite, curving 

 anteriorly. 



Telson as long as the sixth joint. 



Ophthalmopoda as long as the carapace. 



Scaphocerite longer than the ophthalmopod. 



Appendages of the pereion having the basecphyses subequal with the pereiopoda. 



Habitat. — Cape Verde, April 26, 1876. 



The carapace is scarcely more than one-fifth the length of the animal ; it is dorsally 

 armed with a strong tooth in the median line of the gastric region, and anteriorly pro- 

 duced to a rostrum which is broken off in our specimen, so that its length cannot be 

 determined. Near the middle of the orbit stands a large sharp tooth directed forwards, 

 and the antennal angle is rounded off, as is also the frontodateral angle, behind which 

 and within the margin stands a sharp tooth. 



The anterior two somites of the pleon are subequal ; the third is longer, and is armed 

 with an anteriorly curved vertical tooth on the dorsal surface near the posterior margin ; 

 the fourth and fifth somites are shorter and subequal, the sixth is longer than the 

 preceding two, and the telson is equal to the sixth somite. 



The ophthalmopoda are biarticulate and subequal in length with the carapace ; the 

 basal joint being a long and slender stalk that is equal in length to the pyriform distal 

 mass, which corresponds with the usual organ, the rounded extremity of which represents 

 the reticulated ophthalmus. 



The first pair of antennas is longer than the ophthalmopod and terminates in two 



