466 STALK-EYED CRUSTACEA 



laterally compressed, tapering, and has two spines on 

 each side. The eyes are short. The internal antennae 

 have the first joint of the peduncle excavate, and armed 

 with a sharp spine that is subequal with its length. The 

 second and third joint smaller and subcylindrical. There 

 are two flagella, of which the outer is the shorter and 

 more robust. The external antennae have an oval basal 

 scale that has a tooth on the outer margin, and a 

 flagellum which is subequal with the length of the animal. 

 The external maxillipede has an external appendage. 



The first pair of legs is short, stout, and chelate ; the 

 fifth joint is triangulate, and excavated to receive the 

 extremity of the sixth joint. The second pair of legs, 

 slender, slightly longer than the first pair, chelate, has 

 the fifth joint triangulate. The other three pairs of legs 

 short, slightly decrease in length posteriorly, and have 

 their terminal joint spinulose within. 



The gills are attached to the body wall and to the 

 branchial plate of the first maxillipede. 



I. Hippolyte bidentatus. 



Hippolyte bidentatus . . . Spence Bate. 



Rostrum half the length of the carapace ; a small 

 tooth upon its upper margin, half- way between the 

 orbital margin and apex ; the lower margin has a similar 

 tooth a little in advance of the one above. Supraorbital 

 tooth well developed. The fifth abdominal segment has 

 two sharp teeth on the posterior margin. The telson has 

 its extremity truncate and is furnished with a spine at 

 each angle, and it has a large spine on its inner side. 

 The eyes are about half the length of the rostrum. The 

 internal antennae are slightly longer than the rostrum. 

 The basal scale of the external antenuct is subequal in 



