Amphipoda and Isopoda 215 



Length of the single specimen, a female with incubatory lamellfe, 

 and therefore presumably sexually mature, 9-5 millimetres from the 

 anterior border of the head to the tip of the telson. 



The generic position of this species is at present a matter of some 

 doubt. I am unable to speak with certainty as to the structure of the 

 branchial vesicles, and failing precision on this point, the species is 

 provisionally referred to the genus Anonyx, to which it, at any rate, 

 seems most closely allied. It differs from all the other species of the 

 genus in its less compact and more slender form, in the absence of 

 eyes, in the want of distinctly forwardly projecting lateral lobes to the 

 head, in the very prominent and projecting epistomal plate, and in the 

 rounded epimera of the third segment of the metasome. The form of 

 the head closely resembles that seen in the genus Cyclocaris, but the 

 structure of the first gnathopods is quite sufficient to exclude it from 

 that genus. The latter character would also seem to separate it from 

 the genus Tmetonyx 1 ( = Hoplonyx, Gr. 0. Sars), to which, however, its 

 mouth parts more closely approximate than they do to those of 

 Anonyx, though the differences from either genus are at most slight. 

 It would be hazardous to define a new genus for its reception in the 

 absence of definite information on the structure of the branchial 

 vesicles. In the meantime it appears to be distinct, specifically, from 

 all known species of either of the three genera, Anonyx, Tmetonyx, 

 or Cyclocaris. The species is named in honour of its discoverer. 



Isopoda. 



Family, J&gidm. 



Genus, Xenukjlga, nov. 



The mouth parts in the single specimen of this new genus available 

 were not dissected, and, in the absence of information on this point, 

 the new genus may be defined as follows : 



Body depressed, with the cephalon very small, and the metasome 

 distinctly narrower than the mesosome 

 1 See Stebbing, ' Das Tiei-reich. 1 21 Lief., Amphipoda, i., Gammaridea, 1906, p. 73. 



