39 



The 3rd pair of thoracic legs have have a podobranch, and the 1th pair 

 an epipodite. The pleurobranchiae in advance of somite XIV, though small and 

 slender, are plumose and functional. 



The branchial formula is as follows : 



Total 



54? ep. 



64-1 small 1 + 6 small = 1747 small 4- 7ep. 



17. Arlst'ceus (Aristceomorpha) rostridentatus, Sp. Bte. 



Arittieus rostridentatus, Spenoe Bate, Challenger Crustacea Macrurn, p. 317, pi. li. J . 

 Aristseomorpha rostridentata, Wood-Mason, Ann. Mag. Nat. Hist., Oct. 1891, p. 286. 

 ILLUSTRATIONS OF THE ZOOLOGY OF THE INVESTIGATOR, CRUSTACEA Ft. II. Fi<;. 1. 



Finely and very deciduously pubescent. 



Rostrum in the female about two-thirds the length of the rest of the cara- 

 pace measured in the mid-dorsal line, double-curved, markedly elevated at base, 

 armed dorsally with 10 or 11 teeth of which the anterior 5 or 6 are small and 

 distant; its carina is lost on the gastric region. Cervical groove indistinct. 

 The post-orbital ridge is obtuse, but the other ridges and grooves of the cara- 

 pace are very distinct. 



The 6th abdominal somite is about half as long again as the 5th. The 

 acute telson is at least as long as the endopodite of the caudal swinmieret, and is 

 armed bn either side with 4 spi miles. 



Byes large, globular, wider than their stalk : tubercle on eyestalk indistinct. 



The outer antennular flagellum is shorter than the first joint of the peduncle, 

 the inner is longer than the entire body. The antennal scale reaches a little 

 beyond the antennular peduncle. 



The second joint of the mandibular palp is triangular with the postero- 

 internal angle somewhat produced. The exopodite of the 2nd maxillipeds is of 

 extraordinary length. 



The external maxillipeds are stouter than any of the legs, the 3rd pair of 

 legs reach to their tip. The first pair of legs are a good deal shorter than the 



