186 STALK-EYED CRUSTACEA. 
except near the tip, where it is bent up at a small angle, acute, armed 
with four teeth above. A dorsal carina, continuous with the rostrum, runs 
the length of the carapace ; it is armed with one tooth on the posterior part 
of the gastric region. The cervical groove is very deep, but does not cut 
the dorsal carina. Another deep groove runs backward and then diagonally 
upward from the cervical groove toward the posterior border of the cara- 
pace, stopping just short of the posterior margin. The antennal region is 
well defined by the cervical groove below and a gastro-antennal groove above. 
There is a strong antennal tooth on the margin of the carapace, below the 
orbit, another at the antero-inferior angle of the carapace, a third just behind 
the groove that marks the posterior limit of the antennal region, on a level 
with the antennal tooth, and a fourth on the hinder edge of the cervical 
groove, at a lower level than the third. Above and behind the last men- 
tioned tooth the cervical groove is indented, and the upper angle of this 
indentation tends to assume the form of a small tooth or spine. 
The fourth, fifth, and sixth abdominal segments are carinated on the 
median dorsal line and produced into teeth posteriorly. Of these teeth the 
one on the sixth segment is the longest, and it is directed horizontally back- 
ward. The telson is deeply grooved on the dorsal side, and armed near the 
tip with one pair of spiniform lateral teeth. 
The eyes are very large, black, mounted on short stalks. The antennules, 
with their long flagella, surpass the length of the whole body ; the external 
margin of the basal segment of the peduncle is armed with two small teeth, 
one of which is situated near the middle, the other at the distal end; the 
process to which Spence Bate gave the name prosartema is oval, foliaceous, 
and reaches forward as far as the posterior border of the upper face of the 
cornea. 
The peduncle of the second antenne is armed with a prominent external 
spine. The scale is nearly as long as the rostrum, very broad to the distal 
end, membraneous in texture, with the exception of the outer side, which is 
stiffened by caleareous deposit. The flagellum is very long, exceeding by 
much the antennular flagellum. 
The mandibular palpi are long triangular in shape, setose, the terminal 
segment narrow ; they extend forward to the middle of the fourth segment 
of the antennal peduncle. 
The third maxillipeds reach forward to a point a little beyond the distal 
end of the antennal scales. 
