136 HAWAIIAN AND OTHER PACIFIC ECHINI. 



Aceste. 



Wyville Thomson, 1877. Voy. Challenger. The Atlantic, 1, p. 376. 

 Type, Aceste bellidifera Wyville Thomson, 1877. hoc. cit. 



Mortensen's fear that this generic name might have to be rejected or 

 modified because of the use of Acesta in 1855 for a mollusk does not seem to me 

 well founded. The two names both in sound and appearance are sufficiently 

 different. 



Specific differences in Aceste are very slight and that there is really more than 

 a single species seems doubtful. Through the kindness of Mr. Austin H. Clark 

 of the United States National Museum, a fine specimen of bellidifera was avail- 

 able for comparison with the Albatross material. I have been over the ground 

 already pretty completely covered by Agassiz, Mortensen, and Koehler, and have 

 little to add to their statements. This review work has satisfied me that the 

 forms called by Mr. Agassiz and myself ovata and purpurea are really identical 

 but seem to be constantly different from bellidifera. I do not see how Koehler's 

 annandalei is to be distinguished from ovata and must confess that I am inclined 

 to consider the same author's weberi (based on a single specimen collected by 

 the Siboga and identified by de Meijere as bellidifera) as open to grave doubt. 

 The truth is we know almost nothing as to the extent of individual diversity 

 in the genus and it does not seem that Dr. Koehler has made sufficient allow- 

 ance for it. It may be added here that by the same unfortunate lapsus cala?ni 

 referred to above (p. 134), by which Aeropsis sibogae is called A. weberi, the 

 Aceste properly designated weberi is called A. sibogae. 



Key to the Species of Aceste. 



Test sloping forward from apex very distinctly; height near anterior end much less than 

 at posterior. 



Height of test more than half length; sternum and a sort of lower lip formed by the 



labrum prominent bellidifera. 



Height of test not more than half length; sternum and labrum not projecting . . . ovata. 

 Test sloping forward from apex very little; height at anterior end nearly equal to that 



at posterior weberi. 



Aceste bellidifera. 



Wyville Thomson, 1877. Voy. Challen(;kr. The Atlantic, 1, p. 376. 



!'V\v specimens of this species are known and we therefore lack informa- 

 tion aboui growth-changes and individual diversity. All known specimens 



