Chilton. — Amphipodan Genera Bircenna, Kuiia, and Wandelia. 61 



very different, it is probable that comparatively little importance should 

 be attached to this point. 



The possession of a double telson is more important, and distinctly 

 marks these two genera off from the rest of the family ; but this seems 

 to me to point rather to the necessity for slightly enlarging the characters 

 of the family than for the establishment of another family, and I therefore 

 leave the two genera under the Phliantidce, where Chevreux placed his 

 Wandelia. In both species of Bircenna — i.e., B. fulva and B. crassipes— 

 the pleopoda have the peduncle broad and laterally produced, as in other 

 members of the family. 



I give below the arrangement I suggest for these forms, with the 

 characters that appear to me most important for differentiating them. 

 I have shortened the diagnosis of Bircenna, as that given by Stebbing in 

 " Das Tierreich Amphipoda " appears to me to include some details that 

 are hardly likely to prove of generic value ; indeed, some of them have 

 to be omitted to include the second species {B. crassipes). The characters 

 given are, of course, additional to those of the family, and these have not 

 been repeated in the generic diagnoses. 



Fam. PHLIANTID.E. 



Phliadidre, Stebbing in Trans. Linn. Soc, London, ser. 2, vol. vii, p. 414 

 (1899). PJdiantidce, Stebbing in "' Das Tierreich Amphipoda." p. 200 

 (1906). 



Genus Bircenna, Chilton. 



Bircenna, Chilton in Trans. N.Z. Inst., vol. xvi, p. 264 (1884). Bircenna, 

 Stebbing in " Das Tierreich Amphipoda," p. 205 (1906). Wandelia, 

 Chevreux in Exped. Antarctique Franjaise, 1903-5, " Crustaces 

 Amphipodes," p. 44 (1906). 



Body broad, almost cylindrical, pleon segment 5 very short, 6th indis- 

 tmct. Side-plates all very shallow. Maxillipedes with inner and outer 

 lobes long, both reaching apex of 2nd joint of palp, which, though short, 

 contains 4 joints. Gnathopoda 1 and 2 slender and almost simple, similar. 

 Perpeopods short, the 3rd to 5th with the 2nd joint much expanded, and 

 the 4th joint rather expanded and decurrent. Uropoda short, 3rd uni- 

 ramous, lamelliform, peduncle and branch not clearly distinguishable. 

 Telson split to the base, each half subtriangular. 



1. Bircenna fulva, Chilton. 



B. fulva, Chilton in Trans. N.Z. Inst., vol. xvi, p. 264, pi. xxi, figs. 1, 1 a-e 

 (1884). B. fulva, Stebbing in "Das Tierreich Amphipoda," p. 205 

 (1906).. 



Gnathopods similar, not longer and only slightly more slender than 

 the 1st and 2nd pera?opods ; 3rd joint longer than broad, as long as 4th ; 5th 

 a httle shorter than the 6th, which is not expanded, but a little produced 

 at apex, yet not enough to make a chela with the short apically toothed 

 finger. Uropod 1 with peduncle much shorter than the acute curved rami, 

 outer ramus much shorter than inner ; uropod 2 similar, but stouter and 

 shorter; uropod 3 apparently consisting of a single joint, bifid at end, 

 outer apex rounded and bearing a few setse, inner pointed and with only one 

 or two setce. Telson, each half subtriangular, but with apex broadly 

 rounded, with a small seta on each half. Length, 3 mm. 



Lyttelton and Otago Harbours, New Zealand. 



