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Group of G. tringa. 



This is an exceedÏDgly difïicult section, and one of 

 which several local foims, if not distinct species, are 

 represented in the Pacific région, but no satisfactory 

 conclusions can be based upon the beach-worn material 

 wbich at présent is alone available in any quantity. Then 

 again, the identity of C. tnruju, C. zelina and C. fUiia canuot 

 be fixed with certainty from the original descriptions, and 

 so much confusion bas arisen from the indiscriminate use 

 of thèse names that it would perhaps be the better plan to 

 discard them altogether. 



Group of C. albina 



Hère again, the available material is so poor that it is 

 impossible to be certain whether the numerous forms 

 referable to the group are merely variations of a single 

 protean species, C.liyula, Duel., or whether there are in 

 reality several distinct species of this type inhabiting the 

 Pacific and Indian Océans. Certainly when a large séries 

 from différent localities is examined it becomes impossible 

 to draw any sharp conchological distinction between 

 C. albina, Kien. and C. ligula ; but judging from the varions 

 séries which bave reached me (l bave not had the oppor- 

 lunity to collect any examples of this group myself), I am 

 of the opinion that the numerous variations are more or 

 less constant local forms. 



C. austrina, Gask. (i. e., C'. margarita, Rve.) The shells 

 from the islands of the Pacitic which hâve ben referred to 

 C. austrina do not belong to Gaskoin's Australian species, 

 although they resemble itvery closelyatfirst sight, but are 

 in reality somewhat worn and strongly coloured examples 

 of C. margarita. I believe that, in the first instance, I was 

 myself responsible for this erroneous détermination. 



