PROF. F. J. BELL ON THE ECHINOMETRID.E. 



423 



1881.] 



rate, of those purchased at that time from Mr. Gould is a represeu- 

 tative of E. subangularis '. 



ECHINOMETRA LUCUNTER. 



The use of the percentage method in detecting variations, and the 

 extent of the variations themselves, seem to be well shown in this 

 Table. 



ECHINOMETRA SUBANGULARIS. 



It may be well to direct attention to the fact that the longest axis 

 is very little longer than the morphological axis, another point in 

 which Echinometra contrasts very strongly with the two genera which 

 here precede it. 



Echinometra vanbrunti. 



' In a conversation with Mr. Howard Saunders I was reminded that there 

 is a Houtman's Abrolhos on the western coast of Australia ; and I have now no 

 doubt that the registrar of the specimens in the year 1844 did not sufficiently 

 distinguish between the two localities. 



