IV. DESCRIPTION OF GENERA AND SPECIES. 



Conspectus of the Genera, based on the Females. 



A. Abdomen is found, it protrudes from tlie trunli, is comparatively ratlier small, imseg- 

 mented and not set off by an articulation. Eggs are laid in one free lump or in a two 

 (or three) lumps without distinct shape. (Live in the marsupium of Stenothoidse , a 

 family of Ampliipoda) I. Stenothocheres n. gen. 



B. Abdomen is wanting, though caudal stylets are frequently found. Eggs are laid in a 

 smaller or greater number of ovisacs. 



a. Genital area is found; genital apertures close together and surrounded by a common 

 plate, ring or semi-circle, which is more solidly chitinised than the remainder' of the 

 skin. The entrances into the two receptacula seminis are situated within the genital 

 area. The ovisacs are deposed freely. 



a. Trunk-legs and caudal stylets apparently consist of a very small, short basal 



part which tapers into a comparatively rather long and very narrow conical 



branch. Live in the branchial cavity of Cumacea. . 11. Homoeoscelis n. gen. 



§. Trunk-legs and caudal stylets not unfrequently wanting; if found, they are 



very small, generally sub-cylindrical and terminating in two — the caudal 



stylets sometimes in one or three — setae. Live in marsupia. 



§. Maxillipeds good-sized and at least always longer than the maxillae. Live 



in the marsupium of Amphipoda, Cumacea and Isopoda. III. Sphceronella Sal. 



§§. Maxillipeds quite rudimentary, several or many times shorter than the 



maxillae. Live in the branchial cavity of Hippolyte Leach, a genus of 



Decapoda IV. Ghoniostonia H. J. H. 



b. Genital area wanting; the genital apertures often situated at a considerable distance 

 from each other, each having its own arch or ring of solid chitine. The odd recep- 

 taculum seminis is far from the genital apertures. The ovisacs liinged on the lips 

 of the genital apertures. 



