468 STALK-EYED CRUSTACEA 



slender, the outer one usually having a thick base and a 

 thin extremity. The first maxillipede has six joints ; it 

 has a branchial plate. The external maxillipede is long. 

 The first pair of legs resembles the external maxillipede. 

 Of the second pair of legs, the right is the larger. The 

 three last pairs of legs are not very long ; the posterior 

 margin is usually fringed with sharp spine -like teeth. 

 The abdominal appendages have long basal joints. The 

 gills spring from the body wall, the membrane between 

 the body and the first joint of all the limbs, except the 

 first and last pair, and from the base of the first maxilli- 

 pede. 



Range. — West Indies, Philippine Islands, Japan ; in 

 deep water. 



Synopsis of the Species. 



A. The median keel and rostrum have seventeen teeth 

 above and eight teeth below. The flagella of the internal 

 antennae are longer than the rostrum. — (//. ensifei-^ 



B. The median keel and rostrum have fourteen teeth 

 above and nine below. The flagella of the internal 

 antennae are not as long as the rostrum. — (//. o?yx.) 



I. Heterocarpus ensifer. 



Hetei-ocarpus ensifer ... A. Milne Edwards. 

 Pandaliis cai-inatus . . . Smith. 



The carapace is thick ; it has on each side two keels 

 which extend from the base of the external antennse 

 to the external border, and arise in front from a small 

 spine ; a third parallel keel, but much less marked, is 

 seen above the preceding. There is a projecting median 

 keel along the whole length of the carapace, which is 

 continued in front into a long and upcurved rostrum ; 



