Chilton. — -New Zealand Sand-hoppers. 293 



Dana, Spence Bate, and others. In 1881 (p. 208) G. M. Thomson gave 

 a critical review of some of the species, and in 1899 he published a 

 "" Synonymy of the New Zealand Orchestidae." In 1906, in Das Tier- 

 reich Amphipoda, Mr. Stebbing included the New Zealand species and 

 gave brief diagnoses of them. In preparation for his paper Mr. Thomson 

 had made many drawings of the different species, but these were not pub- 

 lished, nor is Stebbing's list illustrated. Mr. Thomson has since handed 

 over to me all his specimens, drawings, and notes. Some of these have 

 been used in the preparation of this paper, and the others will be of great 

 use when it is possible to compile a complete and critical list of the New 

 Zealand Orchestidae. 



At present, however, I deal only with the species of the genus Tal- 

 orchestia. Of these there are three, and for them I accept the names as 

 ■jiven by Stebbing in 1906, adding figures and notes on their distribution 

 and habits which will, I hope, be sufficient to enable local collectors to 

 identify their specimens. 



All three species, with the possible exception of P. lundda, are endemic 

 to New Zealand, and appear to be pretty distinct from the species of the 

 genus found in other countries. 



Genus Talorchestia Dana, 1852. 



Talorchestia Stebbing, 1906, p. 543. 



Stebbing defines Talorchestia by its differences from Orchestia, which he 

 places before it in the list, and Orchestia is defined by reference to Talitrus. 

 The three genera are very close to one another and to Talitroides and 

 Orchestoidea, the five together forming a fairly well defined group of the 

 Orchestidae. 



The following definition of the genus will perhaps be sufficient for the 

 New Zealand species ; I omit, of course, the characters common to the 

 family. 



Antenna 1 shorter than peduncle of antenna 2 ; antenna 2 often 



strongly developed, especially in adult males. Gnathopod 1 small, 



simple in the female, subchelate in the male owing to the production 



of the propod into a narrowly rounded pellucid lobe, a similar lobe 



being usually present on the hind margin of the carpus near the 



distal end. Gnathopod 2 small and feeble in the female, the propod 



being produced into a rounded pellucid lobe beyond the minute 



chela-forming finger. Gnathopod 2 in the male very large and 



powerfully subchelate. Peraeopod 2 with the finger notched or 



otherwise modified and differing from that of peraeopod 1. 



While the three genera are undoubtedly very closely related, Talitrus 



is distinguished by having the second gnathopod small and feeble in the 



male and similar to that of the female. In Orchestia the first gnathopod 



is usually subchelate in the female as well as in the male, and in the male 



the pellucid lobes on the carpus and propod are broader than in Talorchestia 



and differently shaped ; in Orchestia, again, the finger of the second peraeopod 



is usually the same as that of the first. 



The genera Talitroides and Orchestoidea are ill defined ; the first should 

 probably be united with Talitrus, and it is difficult to distinguish Orches- 

 toidea from Talorchestia. Another genus, Talitriator, was . established in 

 1913 (p. 109) by Methuen. who says in his diagnosis, " Like Talitrus except 

 for the fifth side-plate . . ." The type is a truly terrestrial species 



