REPORT ON THE AMPHIPODA. 1467 



the rami nearly equal, the inner a little the longer, the outer with the outer margin and 

 lower part of the inner peetinate and a small pointed apes, the inner similar, except that 

 "f the outer margin only the lower part is pectinate; the peduncles of the second pair 

 little longer than broad ; the outer ramus about as large as one of the preceding, the 

 inner considerably larger ; peduncles of the third pair not longer than broad ; outer ramus 

 shorter than the inner, with smooth outer and pectinate inner margin, the inner ramus 

 apparently coalesced with the peduncle, both margins pectinate for most of their length, 

 the pointed apex not quite reaching the end of the telson. 



Telson, reckoning from the bases of the third uropods, broader than long, triangular, 

 with rounded apex, the margins continuous with those of the coalesced segment, 



Length of the figured specimen, in its folded position, two-fifths of an inch. 



Localities. — April 3, 1875, North Pacific, between New Guinea aud Japan ; lat. 

 24° 49' N, long. 138° 34' E. ; surface ; surface temperature, 71°5. Two specimens. 



April 28, 1876, North Atlantic; lat. 17° 47' N, long. 28° 28' W. ; surface, night; 

 surface temperature, 73°. One specimen, half an inch long with the pleon flexed. (Figs. 

 cp.A. and mx*A.) With this were taken two smaller specimens, not having the acutely 

 projecting side-plates, yet probably belonging to this species, and either presenting 

 one of the stages of growth, or being, as Glaus suggests in his description of Eutyphis 

 inermis, a smaller unarmed variety. 



April 29, 1876, North Atlantic; lat, 18° 8' N., long. 30° 5' W.; surface, night; 

 surface temperature, 73°'7. One specimen, with the acute side-plates, and one specimen 

 unarmed. 



Platyscelus rissoinse, Spence Bate. 



1862. Platyscelus Bissoinx, Spence Bate, Brit. Mus. Catal. Amph. Crust., p. 329, pi. Hi. figs. 9, 86, 



86', 8c, 8h, 8L 1 



The species, at least as represented by the Challenger specimen, has a strong resem- 

 blance to Platyscelus ovoides (Risso 1) and also to Platyscelus armatus (Claus), with which 

 latter species Claus supposed Spence Bate's species might be identical, but our specimen 

 is a large one and yet is without the acutely projecting side-plates, which seem to be a 

 distinguishing character of the adult Platyscelus armatus ; the following particulars may 

 be noticed : — 



Lower Antennae not as in the type specimen with "the first three joints subequal," 

 but with the first free joint longer than all the following joints together, the second and 

 third subequal to one another, the fourth much more slender than the third and only 

 half its length ; there is also a minute fifth joint tipped with a little setule. 



1 Though from the numbering the figures 86 to Si appear to refer to " Thyropusferus" (Milne-Edwards), it is clear 

 from the descriptions that they refer to Platyscelus rissoinx; the figures which Milne-Edwards gives of the gnathopods 

 of his Typhis ferus are quite different and are not copied in the British Museum Catalogue, which gives only the full 

 figure and the upper antennae of that species. 



