466 STUDIES ON AUSTRALIAN MOLLUSCA, X., 



The radula of Elenchus badius Wood, is figured and described 

 by Troschel.* The species spreads along the whole of extra- 

 tropical Australia. On the east coast I have seen it from Caloun- 

 dra, and on the west, Adamsf cites it as P. lineata from Swan 

 Point. 



The shape of this shell is moulded by its environment, for the 

 mollusc lives not on rocks but ever afloat on swaying bands of 

 kelp. The stream has no grip on the smooth lines of C. eximius, 

 as it would have on a normal keeled pyramidal Cantharidus. 

 Some land-shells living on twigs and leaves have assumed a like 

 form under like conditions. 



Cantharidus lineolaris Gould. 



Gould, Proc. Boston Soc. Nat. Hist. viii. 1861, p. 14. 



A photograph of Gould's specimen in the U. S. National 

 Museum shows this to be the shell to which H. & A. Adams, 

 twenty-two months later, gave the name of Leiopyrga picturata, 

 and which was first figured in the Zoology of the "Alert." 



Another photograph from the U.S. National Museum supports 

 my conjecture^ that Bankivia lugubris Gould, is a colour-variety 

 of Cantharidus fasciatus Menke. 



Calliostoma arruense Watson. 



Trochus (Ziziphinus) arruensis Watson, Journ. Linn. Soc. Zool. 

 xv. 1880, p.91; Chall. Rep. Zool. xv. 1886, p.57, Pl.vi. f.5. Can- 

 tharidus torresi Smith, Zool. Coll. " Alert," 1884, p.72, Pl.vi. f.A. 



I owe the above synonomy to my correspondent, Mr H. B. 

 Preston, who bases it on an inspection of types. It is a parallel 

 case to Pleurotoma sterrha and P. iorresiana, dealt with in the 

 last Part of these Studies, in which a " Challenger" preliminary 

 description was overlooked in naming an "Alert" species. Prof. 

 Haddon took this shell at Murray Island, Torres Straits. It 

 occurred to me at Masthead Island, but was misnamed C. similare 



* Gebissd. Schneck. ii. 1879, p.236, Pl.xxiv. f.4. 

 f Proc. Zool. Soc. 1851 (1853), p. 154. 

 + Mem. Austr. Mus. iv. 1903, p. 334. 



