AMPHIPODA. CHILTON. <>7 



Atylu* monoculoides Haswell, but left K. crassi as a dis- 

 tinct species. In 1909 I identified specimens from the 

 Auckland Islands with E. crassi and gave various reasons 

 for the opinion that it could hardly be kept as a species 

 distinct from E. monoculoides (i.e., E. caesaris and E. 

 /tonrpeii). I also pointed out that my specimens appeared 

 to be nearly identical with Bovallia, yiyantea as described 

 by Pfeffer and Chevreux. In 1912, after comparing speci- 

 mens gathered by the "Scotia" with co-types of BovdUni 

 yiyantea, I remained still of -the same opinion. In 1913, 

 p. 168, Chevreux advanced several reasons for considering 

 ft ova-Ilia yiyantea distinct from B. monoculoides. In draw- 

 ing up these differences he has, I think, based some of them 

 on the published descriptions of K. caesaris. It has been 

 pointed out by Walker. Stebbing and myself that in B. 

 monoculoides there are very considerable variations in the 

 presence and acuteness of the dorsal teeth and in the 

 amount of serration of the posterior margin of the third 

 pleon segment. Certainly extreme forms of E. monoculoides 

 (i.e., E. caesaris} and B. yigantea look considerably 

 different, but if we are to unite under one species E. 

 caesaris, E. pompeii and E. monoculoides, then the differ- 

 ences between these forms and Bovallia yiyantea do not 

 seem to me to be sufficient to warrant us in keeping them 

 distinct from that species. Whether the different forms 

 are to be distinguished by different names or not is a point 

 of comparatively little importance, the main point is to 

 ascertain the characters of the forms under consideration 

 and the amount of variation they show. This will be illus- 

 trated by the following brief description of the specimens 

 gathered by the ' ' Endeavour. ' ' 



Off the Tasmaiiian Coast, four specimens (Reg. No. 

 E. 5352) were collected. One of these is a female fully 

 20 mm. long with recently hatched young in the brood 

 pouch. Both upper and lower antennae agree well with 

 the figures given by Stebbing for E. caesaris and also with 

 those given by Chevreux for Bovallia yiyantea, except that 

 the calceoli are not so numerous on the peduncular joints. 

 The third pleon segment has the posterior margin convex 

 and without serrations, the angle being very slightly pro- 

 duced, in this respect agreeing with both E. crassi and 

 B. yiyantea. None of the segments are produced dorsally 

 into teeth ; the fourth pleon segment shows a depression, 

 more distinctly marked than in Stebbing 's figure; the fifth 

 segment is produced posteriorly into a short median tri- 

 angular tooth, which in side view appears as a narrow 



