REPORT ON THE SCHIZOPODA. 



63 



extensive use of the surface-net on the ExjDeditiou proved highly successful. In regard to 

 the capture of Euphausidians this may pre-eminently be said to be the case, scarcely a single 

 haul failing to yield some of the forms comprised in this group, either adult or larval. 

 I have carefuUj^ gone over a vast number of surface gatherings, kindly sent me b}" Dr. 

 John Murray, and from these have selected every form that belongs to the Euphausiidje. 

 A large proportion of the specimens thus brought together represent various stages of 

 development ; and it has therefore been a matter of no slight difficulty to determine in 

 each case with full certainty whether the specimens should be regarded as adults, or 

 whether merely as younger animals. I have been equally perplexed in attempting to 

 refer the larval forms accurately to the several species. Meanwhile, a careful study of 

 numerous specimens has finally enabled me to trace the development of at least three 

 different forms belonging to as many genera, and I shall give a detailed account of these 

 researches when treating of the development of the Euphausiidge. 



The total number of species represented in the collection amounts to no less than 

 twenty-seven, comprising seven distinct genera, of which four are new. 



I give below a synopsis of the genera, worked out from the structure of the legs. 



Legs 



nearly uniform in 

 structure, and simi- 

 lar in appearance 

 to the maxiJlipeds. 



Both, the two posterior pairs quite rudimentary, Euphausia, Dana. 



[ of same appearance as 

 Last pair only rudi- I preceding, 

 ntarv : Denulti- J. 



mentary ; 

 mate pair 



jDenulti- 



I with ■ outer joints 

 [ stem confluent, 



of 



All the legs distinctly developed. 



somewhat unequally 

 developed, one of 

 the anterior pairs < 

 heing greatly elon 

 gate. 



First pair of legs greatly 

 produced and 



rather strong, the two 

 last joints armed with 

 spiniform bristles on 

 both margins, 



very slender, filiform, 

 naked, with only a 

 tuftof apicalbristles, 



Second pair of legs greatly produced; penulti- 

 mate joint dilated, and forming, together with 

 the last one, a kind of prehensile hand. 



Tliysanopoda, M.-Edw. 



Nydiphanes, G. O. Sars. 

 Bentheuphaima, n. gen. 



Tliysanoessa, Brandt. 

 Nematuscelis, G. O. Sars.- 

 Stylocheiroii, G. 0. Sars.- 



Genus 1. Euphausia, Dana, 1852. 

 Euphausia, Dana, United States Exploring Expedition, vol. xiii., Crustacea, part i. p. 639. 



Genetic Characters. — Carapace vdih antero-lateral angles but slightly produced, rostral 

 projection, as a rule, small. Tail powerfully developed. Eyes of normal structure. Anten- 

 nular peduncle alike in both sexes, cylindrical, basal joint sometimes provided at the end 

 superiorly, with a small lappet ; both flagella elongate, and consisting of numerous joints. 



