58 Ti'ansactions. 



respects the 1st gnathopod is closely similar to tlie 2nd gnathopod. Some 

 or all of the setae in the transverse rows on the posterior margin of the carpus 

 in both gnathopods are finely serrate. 



The differences in the 2nd gnathopod between the Rona Bay specimens 

 and the Mount Anglem one are perhaps sexual. The Rona Bay specimen 

 described is a female, bearing eggs in the brood-pouches, while the Mount 

 Anglem specimen, with the larger and more oval propod in the 2nd gnathopod, 

 is probably a male ; but, as the few Rona Bay specimens that I have appear 

 to be all females, this point cannot at present be definitely settled. 



Fam. Talitrid.^:. 



Chiltonia mihiwaka (Chilton). 



Hyalella mihiivaka, Chilton in Ann. Nat. Hist., ser. 7, vol. i, p. 423, pi. xviii 

 (1899). Chiltonia mihiwaka, Stebbing in " Das Tierreich Amphipoda," 

 p. 555 (1906). 



This species was described from specimens found in mountain-streams 

 near Dunedin. During the recent subantarctic expedition specimens were 

 collected both at the Auckland Islands and at Campbell Island. Mr. 

 0. A. Sayce has described 2 species from the fresh waters of Victoria — one, 

 C. australis, has the 3rd uropod less reduced, and consequently approaches 

 more nearly to the genus HyaJella ; the other species, C. subtenuis, is more 

 typical of the genus as regards the 3rd uropod, and is apparently closely 

 related to C. mihiwaka, but differs in having shorter antenna? and a more 

 slender body. 



The genus Hyalella, to which Chiltonia is closely related, is well repre- 

 sented in the fresh waters of America, particularly in South America. Many 

 species have been described from Lake Titicaca by Faxon,* and more re- 

 cently by Monsieur Edouard Chevreux.f The various species, although 

 all closely related, show a great variety in the form of the body, the pro- 

 jection of the different segments into spinal processes, and so on. 



Parorchestia tenuis (Dana). 



Orchestia tenuis, Dana in P. Anier. Ac, vol. ii, p. 202 (1852). Orchestia 

 tenuis, Dana in U.S. Expl. Exp., vol. xiii, ii, p. 872, pi. lix, fig. 1 (1853 

 and 1855). Parorchestia tenuis, Stebbing in '' Das Tierreich Amphi- 

 poda," p. 557 (1906). 



This species has been frequently mentioned by previous authors, but, 

 as with many species of the Orchestido', it is very difficult to identify with 

 certainty, and considerable confusion has arisen with regard to it. It has 

 been recently redescribed by Mr. Stebbing, and I refer to the species (as 

 defined by him) specimens obtained in a fresh-water stream at Rona Bay, 

 AVellington Harbour, and others obtained in similar situations at Akaroa 

 and elsewhere. I also found it on the seashore at Campbell Island, at the 

 mouth of a small stream, and it seems probable that it is a species which 

 can live either in brackish or in fresh water, and perhaps, like many 

 other OrchestidcB, it may be also more or less terrestrial in habit. 



* Bull. Mus. Comp. Zool. Harvard College, vol. iii, No. 16 (Cambridge, Mass., 1876). 

 t "Les Amphipodes des Lacs des Hants Plateaux de TAnierique du Sud" (extract 

 from Mission scientifique, G. de Crequi Montfort et E. Senechal de la Grange). 



