626 THE VOYAGE OF H.M.S. CHALLENGER. 



pereiopoda is not chelate. The second pair is chelate and has the carpos niultiarticulate. 

 The succeeding three pairs are simple. The pleopoda are biramose. The rhipidura is 

 well developed and strong. 



This family contains several genera and connects the Hippolytiche with the 

 Pakemonidae. 



Several of the genera in this family much resemble each other in general appearance, 

 but possess special features that offer means of ready distinction, and may conveniently 

 be arranged under the following heads : — 



Hetcrocarpus, A. Milne-Edwards. 



Carapace laterally and dorsally carinated. Rostrum armed with teeth only, both 



above and below. 

 First pair of antennas having a rudimentary stylocerite. 

 Second pair of pereiopoda unequal in length. 



Plesionika, n. gen. 



Carapace smooth, carinated anteriorly. Dorsal crest and rostrum armed with teeth 



only, above and below. 

 First pair of antennae having a well-developed and pointed stylocerite. 

 Second pair of pereiopoda unecpial in length. 



Nothocaris, n. gen. 



Carapace smooth. Dorsal crest armed with spines and teeth. Rostrum armed 



with teeth above and below. 

 First pair of antennae having a large and pointed stylocerite. 

 Second pair of pereiopoda unecpial in length. 



Pandalus, Leach. 



Carapace smooth. Frontal crest and rostrum armed on the upper surface with 

 movable spines only, and on the lower with teeth. 



First pair of antennae not longer than the carapace, and furnished with a stylo- 

 cerite that has the apex rounded. 



Second pair of gnathopoda without a basecphysis. 



Second pair of pereiopoda unecpial in length. 



