22 THE VOYAGE OF H.M.S. CHALLENGEE. 



The colour of the animal is uniformly whitish, without any distinct pigmentary 

 deposits. 



The limbs do not seem to differ materially in their structure from those of the two 

 preceding species. The terminal part of the first pair of legs was, however, wanting in 

 the specimen examined. 



Habitat. — The above-described specimen I found among the same sample of dredged 

 material from which the preceding species was derived. The locality is stated as 

 follows: — September 8, 1874, at Flinders Passage, 7 fathoms. 



Family II, Vaunthompsoniid^. 



This family is rather closely related to the Cumidse, from which, however, it diifers 

 materially by the three anterior pairs of legs in the female, and all but the last pair in 

 the male, being provided with well-developed natatory exopodites. From the Lampro- 

 pidse, with which family it agrees somewhat in the general appearance and the thin 

 integuments, it is distinguished by the want of a distinctly defined telson, and by the 

 male having five pairs of strongly developed pleopoda as in the Cumidse. The family 

 comprises at present two distinct genera, viz., Vaunthompsonia, Spence Bate, and Lepto- 

 cuma, G. 0. Sars. Besides, the form described by the author at an earlier date under 

 the name of Leucon anonmlus, from the West Indies, would seem more properly to belong 

 to this family than to the Leuconidaj, representing in all probability another distinct 

 genus. Of these genera only the first is represented in the Challenger collection. 



Genus Vaunthompsonia, Spence Bate, 1858. 

 Vauntlwmpsonia, Spence. Bate, Nat. Hist. Review, vol. v. p. 203. 



Generic Characters. — Form of body not very slender, scarcely compressed; anterior 

 and posterior divisions not sharply defined from each other. Integuments thin, 

 squamous. Carapace only slightly arcuate above; pseudorostral projection very short; 

 antero-lateral angles more or less produced. Eye distinctly developed. Five segments 

 of the trunk exposed behind the carapace. Last caudal segment produced at the end, 

 but without any distinct telson. Antennulse small, similar in both sexes, one of the 

 flagella very minute, uniarticulate. Antennae in female biarticulate, with two strong- 

 ciliated setse, in male shorter than the body. First pair of legs rather elongate and 

 slender ; second pair spinous, with the ischial joint not defined ; penultimate pair in 

 female without any rudiment of exopodite. Pleopoda of male very large, with inner 

 plate uniarticulate, outer biarticulate. Uropoda strongly spinous, scape rather short, 

 both branches biarticulate. 



