228 



area in front. Caudal part of body continuous with the preceding part, and 

 forming below a slight hollow, in which the male is found attached. Marsupial 

 rooms approximate along the middle of the ventral face, though not contiguous. 

 Antennae quite rudimentary, forming 4 extremely small and closely set 

 tubercles just within the frontal margin. Oral cone short, simple. Maxillipeds, 

 as in Notophryxus, folded backwards over the comparatively small cordiform 

 sternal plate. Only a single pair of distinctly developed incubatory plates present, 

 issuing, as in Notophryxus from the bases of the anterior pair of legs. A nar- 

 row longitudinal fold also extends on each side behind the oral area, terminating 

 behind in a projecting lappet, which serves for closing the posterior openings of 

 the marsupial cavities. Legs small, somewhat more slender than in Notophryxus, 

 and densely crowded around the oral area. Pleopoda and uropoda wholly absent. 

 Male with the metasome rather produced and indistinctly segmented, last segment 

 carrying 2 small appendages (uropoda). Parasitic on Mysidse, being, as a rule, 

 attached to the dorsal side of the carapace. 



Remarks. — In some respects this genus agrees with that of Notophryxus, 

 especially as regards the structure of the oral parts and the reduction of the 

 incubatory plates; but in other points it differs rather markedly, for instance in 

 the pronouncedly clypeiform shape of the body in the female, the peculiar form of 

 the cephalic part and the rudimentary condition of the antennae. The male also 

 is easily distinguishable by the different structure of the metasome. 



We know as yet of only a single species belonging to this^genus. For 

 the form described by MM. Giard and Bonnier as A. Sarsi cannot in my 

 opinion be maintained as such. In describing this form, the above authors have 

 fallen into some serious errors as regards the structure of the antennae, oral 

 parts and incubatory plates, and this may easily be accounted for by the fact, 

 that they had for examination only a single specimen, which could not be dis- 

 sected, as it belonged to a foreign collection. 



Aspidophryxus peltatus, G. 0. Sars. 



(PL XCVI). 

 'ophryxus peltatus, G. 0. Sars, Oversigt af Norges Crustaceer, I, p. 72, PI. II, fig.s 12—15. 

 Syti. : Aspidophryxus Sarsi. Giard and Bonnier. 



Specific Characters.— Bo&j of fully grown female oval triangular in out- 

 line, being broadest in front and somewhat attenuated behind, terminating in an 

 obtuse point. Dorsal face slightly vaulted, and exhibiting 5 or 6 indistinct 



