NEW MARINE MOLLUSCA (PL. XIII., XIV., 

 AND XV.). 



By W. L. May. 



(Read 21st November, 1910.) 



TASMANIAN MARGINELLAS. 



Tenison Woods when describing M. cyprseoides in 

 these Proceedings for 1877 remarked, " Tasmania is 

 already rich in this genus." If such could be said when 

 the number of species known here was less than, a dozen, 

 how much more may it be emphasised w^hen the total, 

 with those I am now describing, amounts to some 40 

 species? 



Recent dredgings in our deeper Avaters, from 40 to 

 100 fathoms, have brought to light a great number of 

 new forms, some of which are very distinct species, whilst 

 others vary so greatly in both form and size as to make 

 them exceedingly puzzling. The present paper is an 

 attempt to bring some order out of chaos, and will narrow 

 the work down considerably. In dealing with such a 

 variable group it cannot be hoped that my present work 

 will be final; future discoveries and a larger amount of 

 material may show some of the species to be varieties 

 only. On the other hand some, which I now pass as 

 varieties, may yet be established as good species. 



The main difficulty has been with — 



1st. The group represented by M. angasi, ]\I. halli, ]\I. 

 shorehami, and M. simsoni, to wdiich are now added 'M. 

 connectans and 1\I. indiscreta. 



There is an almost endless variation between these 

 ,'pecies, and it might seem superfluous to add more to 

 them, but connectans seems to be the centre of a some- 

 what fairly defined sub-group distinguished by a gene- 

 rally cylindroid shape, and which seemed to require 

 focussing in a species for general convenience; and 

 indiscreta stands at present at the end of a series in its 



