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 dors.al 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 p-osartcma is oval, foliaceous, 

 and reaches forward as far as the posterior border of the upper face of the 

 cornea. 



The peduncle of the second antennae 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 calcareous 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. 



