26 



Fam. 3. Platyaspidae. 



Characters. Body considerably dilated in front, with the carapace very 

 large and applanated, pseudorostral projection distinct, antero-lateral corners obso- 

 lete. All 5 pedigerous segments distinctly exposed, the 1st being of unusual 

 size. Tail slender and narrow. Antennae and oral parts of a similar structure 

 to that in the Lampropidce. Legs, however, very different, the 4 posterior pairs 

 being quite simple in female, without any traces of exopodites; all pairs in male, 

 except the last, provided with well-developed natatory exopodites. 3 pairs of pleopoda 

 present i male. Uropoda slender, resembling somewhat in structure those in the 

 Lampropidce. Telson distinctly defined, conically tapered, terminating with 3 spines. 



Remarks. I have felt justified in establishing this new family, to include 

 the anomalous genus Platyaspis, formerly referred to the Lampropidce. It is true that 

 in certain points this genus seems to approach that family, namely, as regards 

 the structure of the antennae, oral parts and terminal caudal appendages, as also 

 in the number of pleopoda in the male; but there are several other characters, 

 in which it differs so very essentially, as scarcely to allow of its being included 

 in the said family. The carapace, for instance, is of quite a peculiar structure, unlike 

 that in any other known Cumacea, and the 1st pedigerous segment exhibits a 

 development likewise unique in this order. Finally, the structure of the legs is 

 very unlike that in the Lampropidce, and more resembles that in the Cumidce, at 

 least as regards the female, in which only the 1st pair is provided with exopo- 

 dites. Besides the typical genus Platyaspis, I am of opinion that the genus 

 Chalarostylis of Norman ought to be referred to this family. The latter genus, 

 however, is still but imperfectly known, having only been founded upon a solitary 

 specimen of the male sex. 



Gen. Platyaspis, G. 0. Sars, 1869. 



Generic Characters. Carapace large and broad, slightly vaulted above, 

 sides greatly expanded, fornicate; pseudorostral projection triangular. 1st pedi- 

 gerous segment much larger than any of the others. Integuments rather thin, 

 squamous. Eye wholly absent. Superior antenna? with both flagella well deve- 

 loped and nearly equal, the outer one in male provided at the base with numerous, 



