194 



lamellar, with the distal joint generally well defined and the proximal joint ex- 

 panded inside. Only a single ovisac present in female. 



Remarks. To this family I refer a number of genera, which, as regards 

 both the external appearance and the structure of some of the appendages, exhibit a 

 perplexing similarity to the more typical Diosaccidce (Amphiascus), though differing 

 materially in a few points. Thus in all the forms only a single ovisac is present 

 in the female, and the rostrum never attains that full development which is charac- 

 teristic of the Diosaccidos, being in most cases reduced to a very minute im- 

 mobile point. The outer ramus of the posterior antennse is very small, and this 

 is also generally the case with the mandibular palp. As to the legs,~the 1st pair 

 are often built upon a very similar type to that in the Diosaccidce, the inner ramus 

 being generally longer than the outer, and more or less prehensile. On the other 

 hand, this ramus, in the natatory legs, is as a rule less fully developed than in 

 the Diosaccidce. The present family is represented both in fresh water and in 

 the sea, some forms also in brackish water. 



Gen. 42. CanthOCamptUS, Westwood, 1836. 



Syn: Canthocarpus. Baird. 



Generic Characters. Body slender, cylindric in shape, and very flexible, 

 with the anterior division only little broader than the posterior. Cephalic segment 

 of moderate size and not very deep; rostral projection very small, and rudiment- 

 ary. Epimeral plates of the 3 succeeding segments comparatively small and 

 rounded behind; last pedigerous segment scarcely narrower than the preceding, 

 one, but without true epimeral plates. Urosome well developed, with the segments 

 spinulose at the hind edge ventrally and laterally, genital segment in female large 

 and imperfectly divided in the middle, last segment short, with a distinct anal 

 opercle edged with regular spinules. Caudal rami slightly produced and provided 

 outside with 2 hair-like bristles, apical setae normal. Eye well developed. An- 

 terior antennae more or less slender, 8-articulate, those in male strongly hinged. 

 Posterior antennse with the outer ramus rather small, biarticulate, distal joint the 

 smaller. Oral parts on the whole poorly developed. Mandibular palp simple, 

 biarticulate. Maxillae without distinctly defined exopodal and epipodal plates. 

 Anterior maxillipeds provided with only 2 digitiform lobules inside the unguiferous 

 joint. Posterior maxillipeds normally developed. 1st pair of legs with the inner 



