AMBLYPNEUSTES. 325 



AMBLYPNEUSTES. 



L. Agassiz, 1841. Int. Mon. Scut., p. 7. 

 Type-species, Echinus griseus Blainville, 1825. Diet. Sci. Nat., XXXVII, p. 81. 



In the present state of our knowledge, this is one of the most perplexing 

 genera of recent Echini. The species have always been in confusion, and in 

 spite of Mortensen's excellent work (1904, Dan. Exp. Siam: Ech.), there is 

 still great difficulty in identifying specimens and in determining specific limits. 

 The difficulty has arisen largely from the facts that no trained echinologist 

 has been able to examine these Echini in life, and practically all Museum material 

 has consisted of bare tests, which show great individual diversity in color and 

 proportions. It is only within recent years that our Museums have obtained 

 material with the spines on and even now such material is not common. Mor- 

 tensen's view that no reliance can be placed on the identifications of Amblyp- 

 neustes hitherto is wholly justified and while his work, combined with the results 

 here published, will not make identifications perfectly reliable, they will, it is 

 hoped, increase the possibility of distinguishing the various species. It seems 

 certain however that the truth in regard to the species of Amblypneustes can only 

 be known, when some zoologist in Australia carefully determines the valid species 

 and the limits of individual diversity. This work must be done in southeastern 

 Australia and Tasmania, which is the principal, if not the exclusive home of the 

 genus. I have seen no authenticated specimens from elsewhere and although 

 Amblypneustes has been recorded from the Cape of Good Hope, from the Fiji, 

 and Santa Cruz Islands, from New Caledonia and New Zealand, and from 

 western Australia, all these records need confirmation. There is no doubt that 

 the Cape of Good Hope record is wrong, and that the western Australian record 

 is correct, but there is great doubt as to the others. It is a curious fact that 

 although two species (not to mention Studer's grossularia) have long been listed 

 from New Zealand, the zoologists of the present day there, apparently do not 

 know the genus at first hand. In none of the valuable papers on New Zealand 

 echinoderms by Farquhar or Benham, is there any new information regarding 

 the occurrence of Amblypneustes in New Zealand. 



So far as can be judged from Mortensen's key and from the material in the 

 M. C. Z. collection there are probably half a dozen valid species of Amblyp- 

 neustes; of the eight recognized in the table below, at least two seem very 

 dubious. It is more than possible that ovum and griseus are identical, for 

 although typical examples of each are obviously different, specimens that might 



