88 



a. Maxillipeds good-sized. Genital apertures very far from each other, placed 

 very near the line where the hind margin and the lateral-margin meet. Live 

 in the marsupium of the genera Erythrops G. 0. S. and Parerythrops G. 0. 

 Sars, belonging to Mysidacea V. Mysidion n. gen. p. I 



p. Maxillipeds wanting. Genital apertures closer together, somewhat up on the 

 dorsal surface. Live attached outside on the back and on the sides of the 

 body or on the eye-stalks of the genus Erythrops G. O. Sars, belonging to 

 Mysidacea VI. Aspidoecia Giard and Bonn. D- ' 



I. Stenotliocheres n. gen. 



FEMALE. The body somewhat longer than broad; naked all over. The head which 

 is comparatively good-sized, is not marked out from the trunk; it has neither frontal nor 

 lateral borders. Antennulae comparatively long, without distinct articulation and with few 

 setae. Antennas middle-sized. The mouth-border with very short hairs. Maxillulse without 

 additional branch. Maxillse robust, without hairs. Maxillipeds of scarcely medium size, second 

 and third joints coalescent, all joints without hairs, spines or processes. Sub-median skeleton 

 very feebly developed, consisting only of a plate in front of each maxilliped. The trunk-legs 

 are situated rather far from the lateral margin; they are comparatively of considerable size 

 and consist of a basal part with two unjointed branches, each as a rule ending in a strong 

 or spiniform seta, besides, on the outer branch of the first pair of legs, is found a 

 smaller seta. Abdomen pretty well developed, consisting of a robust basal part and a 

 narrower distal part, which passes without articulation into two short and broad caudal 

 stylets, each of which bears four setae of unequal length. Genital area wanting. Genital 

 apertures situated partly on the lateral surface, partly on the ventral side of the basal part 

 of the abdomen, more or less close to its lateral margin. Two large receptacula seminis, 

 the entrances of which have not been found. — Spermatophores have not been noticed. 



MALE. Agrees with the female in most features, so that only some characters 

 need be pointed out. The head is not marked out, it occupies about half of the body. The 

 trunk-legs are situated at a short distance inside the lateral margins of the trunk ; both pairs 

 are comparatively very considerable, with a thick basal part. A little behind and outside 

 the second pair of trunk-legs proceed a pair of spines (pi. I, fig. 2 1, x), which are possibly 

 the rudiments of a third pair of legs. Only the narrower, distal part of the abdomen can 

 be distinguished from the trunk. The body is naked, but on its dorsal side, and especially 

 on its front part, it is furnished with moderately small, irregular protuberant knots, and on 



