REPORT ON THE SCHIZOPODA. 



29 



255 fathoms [Gnathophausia longispina), the greatest 2200 fathoms (Gnathophausia 

 gigas). Gnathophausia has never been taken at the surface of the sea, although the 

 surface- net was in frequent use during the Expedition, both by night and day, and in many 

 different tracts of the ocean. It may therefore certainly be assumed that these 

 Crustacea, notwithstanding their strongly developed natatory organs, never leave the 

 deeper strata of the sea, and that in all probability they have their habitat on the sea- 

 bottom itself 



To judge from the inconsiderable number of examples of each species obtained by the 

 Expedition, notwithstanding that a large trawl-net was generally in use, it would appear 

 that the animals of this genus lead a comparatively isolated existence, being seldom met 

 with in shoals. 



Distribution. — The genus seems to exhibit a very extensive geographical distribution, 

 being most probably represented throughout the greater part of the ocean, excepting 

 perhaps the Arctic and Antarctic regions. Thus, as will be shown in the sequel, species of 

 this genus have been recorded both from the North and South Atlantic, from the Pacific, 

 and from the seas of the Indian Ai'chipelago. The genus may even be reckoned 

 among the European fauna, one of its species {GnatJiop>hausia zoea) having been found by 

 the French expedition in the Bay of Biscay. 



Classification. — The species may be naturally classed within two or rather three 

 sections or subgenera, chiefly characterised by the form of the autennal scale, the presence 

 or absence of an exopodite on the maxillipeds, and finally by the form of the carapace. 



The following synopsis of the species may be here appended : — 



Autennal 

 scale 



very small, not 

 jointed, outer 

 margin sen-ate. 

 Eostrum 



Synopsis of the Species of Gnathophausia. 



short, indistinctly denticulate, 



large, of usual 

 form, jointed, 

 outer margin 

 terminating in 

 a strong spine. 

 Inferoposterior 

 corners of cara- 

 pace 



( slightly produced, 

 rior ) 



G. ingeiis, Dohrn. 

 G. giyas, Suhm. 



elongate. Infero-posterior 



corners of carapace "^ produced as long ser- 



' rate spines, . . G. calcamta, G. 0. Sars. 



compara- 

 tively short. 



Upper 

 lateral keel 



distinct, f , i 

 ■J-. . sharply 



oUhT i PO''!^"^' G-^'^ttemoem.G.O.Savs. 



rounded 



off Dor- - 



sal spine 



■j caudal I , 

 segments [ 



obsolete, . 



? 1 ^ P, ' of moderate size, 

 duced. An- | 



•ii " ■ i greatly produced and 

 with spme ^JJ ^^ ^^^^ 



of the outer , 

 corner [ 



margins, 

 produced into two distinct spines, 



G. affinis, G. 0. Sars. 

 G. elegans, G. 0. Sars. 

 G. zoea, Suhm. 



G. longispina, G. 0. Sars. 

 G. gracilis, Suhm. 



