352 HAWAIIAN AND OTHER PACIFIC ECHINI. 



been taken at Cape St. Lucas, Lower California, by John Xantus, about 1860^ 

 but if the locaUty is correct, it is remarkable that the explorations of the ''Alba- 

 tross" in the same region have failed to bring other specimens to light. 



Strongylocentrotus. 



Brandt, 1835. Prodrom. desc. Anim., p. 263 (or 63). 



Type-species, Strongylocentrotus chlorocentrolus Brandt, 1. c, p. 264 (or 64) = Echinus drobachiensis O. F. 



Miiller, 1776. Prodrom. Zool. Dan., p. 235. 



Sq homogeneous is this genus and so completely do the forms intergrade that 

 it is almost wholly a matter of opinion as to what species are to be considered 

 valid. It seems nearly certain that the widely distributed drohachiensis is the 

 parent stock from which the others have sprung, but how many species are at 

 the present time fully differentiated from this stock is very hard to decide. Of 

 course a typical franciscanus is very easily distinguished and that is certainly 

 a distinct species, yet it appears to intergrade wdth purpuratus which in turn 

 connects very clearly with drohachiensis. In the European seas, granularis 

 (Lamk.) has become quite an easily recognized species particularly when its 

 characteristic features are fully developed. The Japanese and Aleutian forms 

 are not so well defined and although the attempt to distinguish, from those 

 seas, pulcherrimus A. Ag., depressus A. Ag., intermedins A. Ag., pukhcUus A. Ag. 

 and CI., echinoides A. Ag. and CI., polyacanthus A. Ag. and CI., and nudu^ A. Ag., 

 typical examples of which are easily recognizable, is here made, it is probable 

 that at least two or three of them are not really specifically distinct from droha- 

 chiensis, and ought not to be honored with names. There is not the slightest 

 ground for doubting that chlorocentrolus Brandt is a sj^nonj-m of drohachiensis. 

 Alaskan specimens show very great diversity in the length of the spines as well 

 as in coloration. The name carnosus A. Ag. might well be revived for the very 

 luuidsonie form from northeastern Asia, but as the coloration is not always 

 striking and soonis to intergrade with that of drohachiensis, and as any other 

 distinctive character is not apparent it is Vx'tter to let the case stand as it is, 

 unlil some zo()logist can make a special study, in the field, of the North Pacific 

 forms of vStrongylocentrotus. The form which Dinlorlein (1000, Zool. .Vnz., 

 XXX, p. 517) described from Sakhalin as a variety of drohachiensis under the name 

 sachalinicd, seems to l)e very well characterized by tiie remarkably small number 

 of corotml plates and although specimens have not been seen, it is here raised to 

 specific rank. His proposed species hokk'ai<iensis is however nothing more or less 



