27 



closely set sensory filaments. Inferior antennae in female 4-articulate, in 

 male much shorter than the body. Anterior maxillae without any traces of palps 

 .'>)<! pair of maxillipeds rather unlike those in other Cumacea, the basal joint 

 being quite straight, and not expanded distally. 1st pair of legs comparatively 

 short, resembling in structure the .'!rd pair of maxillipeds, the outer joints partly 

 lamellar. '2nd pair of legs slender and elongated, with the full number of joints, 

 outer part spinous; the 3 posterior pairs exceedingly narrow, and almost 

 naked. Uropoda with the inner ramus longer than the outer and 3-articulate. 

 Telson without lateral spinules. 



Remarks. This genus was established by the present author in the year 

 1869, to comprise the peculiar Cumacean described below, the name being de- 

 rived from the pronouncedly depressed form of the carapace. The genus is as 

 yet only represented by the type species. 



Platyaspis typica, G. 0. Sars. 



(PI. XIX, XX.) 

 Flatt/fisi>ii* tijpica, G. O. Sars, Nye Dybvandscrustaceer fra Lofoten. Chr. Vid. Selsk.Forh. 1869, p. 14. 



Specific Characters. Body moderately slender, with the anterior division 

 considerably dilated, though rapidly tapering behind. Carapace more than twice 

 as long as the exposed part of the trunk, and, viewed dorsally, of oval quadran- 

 gular form, the greatest width occurring behind in female, in male quite in front, 

 dorsal face gently vaulted, with an obtuse keel along the middle, sides lamellarly 

 expanded, forming a horizontally projecting smooth carina, which extends on each 

 side throughout the whole length of the carapace; pseudorostral projection short, 

 almost rectangular. 1st pedigerous segment nearly as long as the 3 succeeding seg- 

 ments combined, and rather broad in front, exhibiting dorsally a saddle-like 

 depression. Tail, including the telson, about the length of the anterior division, 

 and extremely slender. Superior antennae with the outer flagellum in female 

 3-articulate, in male 5-articulate, inner flagellum in female biarticulate, in male 

 triarticulate. Inferior antennae in female with 3 plumose setse, in male scarcely 

 longer than the anterior division of the body. 3rd pair of maxillipeds with the 

 carpal joint rather large, and dilated in its proximal part. 1st pair of legs with 

 the terminal part scarcely longer than the basal joint, ischial joint extremely 

 small, the 3 succeeding joints of about equal size and sublamellar, terminal joint 

 much smaller. 2nd pair of legs scarcely shorter than the 1st, but much nar- 

 rower, antepenultimate joint about the length of the last 2 joints combined, and 

 strongly spinous inside. The 3 posterior pairs extremely slender, and gradually 



