2 W. T. CALMAN. 



in one case a very little behind the orbital notch, and the last two are close to the 

 apex of the rostrum; lower margin with six to nine teeth (usually seven.) No 

 supra-orbital teeth, anteunal tooth distinct from the lower orbital angle, antero- 

 lateral corner of carapace with a minute (pterygostomial) tooth. 



Third abdominal somite with dorsal surface strongly elevated or " humped," 

 but without a definite tubercle as in Chorismus tuberculatus. Sixth abdominal 

 somite without movable lateral spines. 



Peduncle of antennules reaching to or nearly to two-thirds the length of 

 rostrum, third segment one-half the length of second, spine of first segment 

 (" stylocerite ") narrow and acute, reaching to middle or quite to end of second 

 segment ; flagella subequal, or inner slightly longer than outer, extending beyond 

 tip of rostrum by one-third to nearly half their length. Antennal scale broad, about 

 equal in length to rostrum, outer edge distinctly and evenly convex, apex broadly 

 rounded, outer spine short. 



Mandible with small incisor process and palp of three segments, the first broader 

 than, and as long as the second. Third maxilliped extending nearly to tip of 

 antennal scale, terminal segment twice the length of preceding. Exopod well 

 developed. 



First leg extending beyond penultimate segment of third maxilliped, carpus 

 slightly excavate distally, about equal in length to the hand. Second leg extending 

 beyond tip of antennal scale, carpus of eleven, merus of three, and ischium of two 

 segments. Remaining legs moderately stout, fifth leg extending forwards nearly 

 to tip of antennal scale. 



Telson not greatly narrowed distally, tip rounded, with seven spines. Inner 

 plate of uropods subequal to the telson and very little shorter than the outer plate, 

 which is broadly rounded at the tip. 



The branchial system comprises five pleurobranchise on each side on the last 

 five thoracic somites, an arthrobranchia on the third, and a podobranchia on the 

 second maxilliped. There are epipods on the third maxillipeds and on the first two 

 pairs of legs. 



Young males (55-59 mm. in length) and females (42 mm.) Body a little more 

 slender and the rostrum relatively longer, distinctly exceeding the length from orbit 

 to back of carapace. Flagella of autennule little longer than rostrum. Outer edge 

 of antennal scale straight. In two specimens ( $ and ? ) there are twelve segments 

 in carpus of second leg. 



The co-typical specimen of Hippolyte antarctica used for comparison is an 

 ovigerous female, about 60 mm. in total length. It agrees perfectly with the 

 ' Discovery ' specimens except in the following points : Of the seven teeth on the 

 upper edge of the rostrum only one is close to the point, not two, as in our 

 specimens ; the antennal scale is slightly longer than the rostrum, and its outer edge 

 (as in our specimens of similar size) is nearly straight ; the third maxillipeds are a 



