644 THE VOYAGE OF H.M.S, CHALLENGEE. 



different number of the teeth on the rostral crest, and the produced point on the third 

 somite in the female, from which the specific name is derived, being so much reduced in 

 the male. 



This species bears some resemblance to Pandalus martins, A. Milne-Edwards, obtained 

 during the expedition of the " Travailleur," ' from which it chiefly differs in having the 

 rostrum not quite so long, and the serrature of the lower margin stronger, in the presence 

 of the pointed or tooth- like process at the posterior dorsal margin of the third somite of 

 the pleon, and in having the dactylos shorter in the three posterior pereiopoda. 



Plesionika semilsevis, n. sp. (PL CXIII. fig. 3). 



Carapace smooth, rostrum once and half as long as the dorsal surface of the carapace, 

 smooth on the upper surface, minutely serrate on the lower, frontal crest armed with six 

 teeth. 



Pleon smooth and laterally compressed. 



Telson dorsally flat and laterally compressed. 



Ophthalmopoda large, reniform. 



First pair of antennas having the flagella as long again as the rostrum. 



Second pair having the flagellum subequal with those of the first pair ; seaphocerite 

 about half the length of the rostrum. 



Pereiopoda long, but not extremely so. 



Pleon smooth and polished. 



Telson shorter than the outer plates of the rhipidura and equal with the inner. 



Habitat— Station 200, October 23, 1874; lat. 6° 47' N., long. 122° 28' E.; between 

 the Philippine Islands and Borneo ; depth, 250 fathoms ; bottom, green mud. Sixteen 

 specimens ; nine males and seven females, five laden with ova. Trawled. 



Station 164a, June 13, 1874 ; lat. 34° 9' S., long. 151° 55' W.; off Sydney Harbour, 

 Australia; depth, 1200 fathoms; bottom, green mud. Two damaged specimens. 

 Associated with Nothocaris rostricrescentis. 



Station 170, July 14, 1874; lat. 29° 55' 9" S., long. 170° 14' W.; off the Kermadec 

 1 Recueil de Figures de Crustacea nouveaux ou peu connus, 1883. 



