Chilton. — Some New Zealand Amphipoda. 



233 



It seems evident that a good deal more work must be devoted to the 

 genus Corophium before the various problems indicated above can be 

 solved. Probably we are dealing with a widely distributed form which is 

 in the process of development but has not yet differentiated into distinct 

 species, and some of the differences recorded may be associated with the 

 character of the water in which it lives. 



The telson appears to be practically the same in all the specimens — 

 European, Australian, and New Zealand — that I have examined. It is 

 broadly triangular, with the posterior margin truncate or slightly convex, 

 and it bears on the dorsal surface, towards the posterior margin, two ridges 

 diverging anteriorly and each bearing about four minute blunt spines pro- 

 jecting upwards. These ridges do not appear to be described or figured 



B 



Fig. 5. — Corophium crassicorne Bruz. 



A. Telson with second and third uropoda. 



B. Telson (more highly magnified). 



by Sars or Stebbing, though they are indicated in Sars's figure of the telson 

 of C. bonellii (1895, pi. 22, fig. 1, t), and apparently in that of C. affine (I.e., 

 fig. 2, t). The telson shows different appearances according to its precise 

 position when mounted. My specimens, which are all mounted perma- 

 nently in Canada balsam, have become transparent enough to show the 

 two ridges pretty clearly. In a specimen of C. triaeonyx Stebbing from 

 Ceylon the terminal portion of the telson appears to have become doubled 

 underneath, and consequently the two anterior spines extend clearly 

 beyond the visible margin. In another specimen of the same sj)ecies 

 from Chilka Lake, however, the other spines could be clearly made out. 



Phronima sedentaria Forskal. 



Phronima sedentaria Bovallius, 1885, p. 354. P. novae-zealandieie 

 Powell, 1875. p. 21, figs. 1, 2; Stebbing, 1888, p. 1356, pi. 161b; 

 Chilton, 1912a, p. 131. 



This species is frequently washed up on the coast of New Zealand, and 

 I have specimens also from the Chatham Islands. It was described by 

 Powell as a species peculiar to southern seas, but there is no doubt that 

 Bovallius is right in referring it to the northern species sedentaria. A very 

 full description and discussion of the synonyms is given by Bovallius in the 

 reference quoted above. The animal is pelagic, and is invariably found 

 in its " house," which is supposed to be the " test " of a salp or of some- 

 tunicate. The young in various stages of development are frequently found 

 in the " house " with the female, but so far as I am aware nothing is known 

 of the way in which they obtain a " house " for themselves. Males are very 

 rare ; I have not seen one among the New Zealand specimens. 



