— 52 — 



Stylocheiron G. O. S. 



To Sars' diagnosis of this genus some additions and 

 corrections may be made. 



The antennulae in the female with the two distal pedun- 

 cular joints slender and long or extremely long; in the 

 males these joints, and especially the third, shorter and 

 much thicker ; the flagella with only from 6 to 10 joints 

 which in the females are slender and round ; in the males 

 the basal joint of the lower flagellum is long and gradually 

 much thickened towards the base, and is most species the 

 major distal part of both flagella is distinctly flattened and 

 frequently expanded, in some species (S. carinatum, 

 S. maximum, S. abbreviation) even much expanded, in the 

 upper flagellum depressed, in the lower compressed. In 

 the female the endopod of fifth pair of legs is moderately 

 long, three-jointed, the endopod of sixth pair much longer 

 than the small exopod, two-jointed ; in the male the 

 endopod of sixth pair is always wanting, while in fifth 

 pair it seems to be wanting, f. inst. in S. longicome, or deve- 

 loped as in the female in S. maximum. The characteristic 

 male copulatory organs were described in the « Siboga » 

 report (p. 80). 



The genus comprises 9 species": S. carinatum G. O. S., 

 S. insulare H. J. H., S. microphthalma H. J. H., S. affine 

 H. J. H., S. Suhmii G. O. S., S. longicome G. O. S., 

 6". elongatum G. O. S., 5. maximum H. J. H. and S. abbre- 

 viatum G. O. S. As to S. elongatum the ((Challenger» 

 report may be sufficient for the recognition ; the other 

 eight species have been treated in the a Siboga » report, 

 and to the characterization of the species I have nothing of 

 importance to add, but it may be mentioned that all spe- 

 cies enumerated excepting S. insulare H. J. H. are found 

 in the tropical East Pacific (Agassiz Exp.). A detailed 

 study of some of the thoracic legs promises results of 

 interest, but it must be postponed to the report on the 

 Monaco collection. 



