REPORT ON THE SCHIZOPODA. 



137 



two formiug together a kind of grasping organ. Succeeding legs much smaller and 

 rapidly diminishing in length, the two anterior pairs with proximal part much compressed, 

 laminar ; antepenultimate pair with endopod bi-articulate ; last pair quite rudimentary, 

 forming each merely a small setiferous lamella. Gills rather simple in structure, last pair 

 largest. Ovisac single. Only three luminous globules present, one ventral belonging to 

 the first caudal segment, and two lateral at the bases of the penultimate pair of legs, the 

 latter in the male very fully developed and supplied with an additional lens. 



Remarks. — This is a very distinct genus, and characterised most prominently by 

 the strong and peculiar development of the second pair of legs, which are modified so 

 as to form grasping organs. Moi-eover, it differs in several other respects, as will be 

 seen from the above diagnosis, not a little from other Euphausiidse, though exhibiting 

 perhaps a certain affinity to the genus Nematoscelis. 



Five different species of this remarkable genus are represented in the Challenger 

 collection. All of these are comparatively very .smaU, but undoubtedly cannot be 

 regarded as larval stages, since in one of the species at least, both ovigerous females 

 and adult males have been observed. This genus I had previously met with, having 

 observed one of its species in the Mediterranean, at Messina, in the year 1876. 



The following is a synopsis of the species : — 



distinctly carinate above, with a conspicuous rouudeil crest anterior 

 to the middle. Rostrum very narrow, acute. Eyes large, with 

 cornea narrowed in upper part, ..... 



Carapace - 



S. carinuturn, G. 0. Sars. 



but slightly keeled 

 above in anterior 

 part. Eyes 



comparatively small, with cornea very much 



narrowed in upper part. Rostrum acute, . S. mhmit, G. 0. Sars. 



rather large, com- 

 pressed, with cor- 

 nea narrow, ob- 

 long. Last caudal 

 segment 



not longer than pre- 

 ceding. Rostrum 

 acutely produced, . 



exceedingly elongate 

 and slender. Ros- 

 trum very short, . 



remarkably short, with rather jiroduced rostrum. Eyes exceedingly 

 large and thick. Outer part of second pair of legs forming a 

 complete chela, ....... 



S. longicorne, G. 0. Sars. 



S. elongatum, G. O. Sars. 



S. ahbremaium, G. 0. Bars. 



.37. Stijiocheiron cannatum, G. 0. Sars (PI. XXVI.). 



Stylocheiron carinatum, G. 0. Sars, Preliminary Jfotices on the Challenger Schizopoda, JTo. 35. 



Si:>ecijic Cliaracters. — Form of body rather thickset in male, somewhat more slender 

 in female. Carapace short in proportion to height, distinctly carinated above, and 

 forming an elevated crest behind base of rostrum ; the latter very narrow and acutely 

 produced. Last caudal segment longer than preceding. Eyes large, irregularly 



(ZOOL. CHALL. EXP. PART XXXVII. 1885.) Oo 18 



