Chilton. — New Zealand Sand-hoppers. 



301 



the finger the palm bears a rounded spinose process which is followed by a 

 long flat spinose protuberance separated by a concavity from the defining 

 tooth, finger thickened on inner side near the base (fig. 17). Gnathopod 2 

 in the female normal. Peraeopod 5 in 

 male with merus triangular, widening 

 distally, carpus expanded posteriorly 

 into an enormous oval plate, concave 

 on the inner side (fig. 18). 



Length. — About 12 mm. 



Occurrence. — Sandy shores of New 

 Zealand and Chatham Islands, about 

 high-water mark. 



Remarks. — This species is smaller 

 than the other two, and appears to be 

 less common, though it has been 

 taken at several widely separated 

 places from the North Cape of New 

 Zealand to Stewart Island. In Chat- 

 ham Islands it seems to be relatively 

 more abundant, as it occurs in most 

 of the few collections I have had from 

 those islands. In a few cases I have 

 taken it not far from the mouth of a 

 fresh-water stream, but this may be 

 purely accidental. 



The male can be easily recognized 

 by the extraordinary process on the 

 fifth peraeopod ; all stages may be 

 found between a slight flat expansion 

 of the hind margin of the carpus and 

 the huge process shown in fig. 18. 

 A somewhat similar process is found 



in Talorchestia scutigerula (Dana), but in that species it arises as an expan- 

 sion of the second or basal joint. 



I have described this species as having two forms of the male, so far as 

 the second gnathopods are concerned. It is possible, of course, that the 

 second form should be considered a separate species, as its second gnathopod 

 in the male differs very markedly from that of the first form. The animal 

 has, however, the greatly expanded carpus of the fifth peraeopod, and in 

 most other points agrees so closely both in structure and in habits that I 

 prefer to group both forms under the one species. The description and 

 figure of the gnathopod of this second form is taken from a Chatham Island 

 specimen, and apparently all the Chatham Island specimens belong to this 

 form. I have one specimen also, from Ross Beach, Westland, which has 

 the second gnathopod like the Chatham Island form, particularly in the 

 small thumb-like process on the inner side of the defining tooth, but it has 

 the rounded protuberance on the palm near the base of the finger much 

 broader than in the Chatham Island specimens. In the Ross specimen the 

 fifth peraeopod is not fully developed, the carpus being considerably ex- 

 panded but not having developed into the great oval plate characteristic 

 of the species. In the first gnathopod of the Ross specimen the pellucid 

 lobe on the propod is moderately well defined, but there is no sign of the 

 similar small lobe on the carpus, and apparently this lobe on the carpus 



Fig. 17. — Second gnathopod of male, 

 second form (less enlarged than 

 fig. 15). 



