Iredale. — New Zealand Marine Molluscs. 377 



this species is shown by the following : Pritchard and GatlifE 

 (Proc. Roy. Soc, vol. xv (n.s.), p. 195, 1903), in their list of 

 Victorian shells, believed A. cantharus,' Reeve, was a Victorian 

 shell, but could not give it specific rank, citing it as a synonym 

 of A. septiformis, Q. and G. I have examined shells sent by 

 Mr. GatlifE in support of this classification, and I quite agree 

 that the shell so classed is a variant of A. septiformis, Q. 

 and G., but it is certainly not the New Zealand shell called 

 A. caniharus, Reeve. 



Tate and May, in the " Revised Census of the Marine Mol- 

 lusca of Tasmania " (Proc. Linn. Soc. N.S.W., vol. xxvi, p. 412, 

 1901), consider A. caniharus, Reeve, as a distinct Tasmanian 

 species. Mr. May sent me shells identified as above, but they 

 are not A. cantharus, Reeve. They may be an extreme form 

 of A. septiformis, Q. and G., but that point must be settled by 

 a study of the shells in their environment. 



In the Trans. Roy. Soc, S. Aust, vol. xxx, p. 215, 1906 

 (1907), Dr. Veiro identifies a South Australian shell as A. can- 

 tharus, Reeve. He treats fully of the shell so named, and has 

 since expressed the opinion that the South Australian shell 

 is identical with the New Zealand shell. -The specimens he 

 sent me, though very similar, I do not consider conspecific 

 with ours. They are much eroded, whereas the New Zealand 

 shell is very rarely so ; the general coloration, as shown by the 

 literature and these specimens, is the exception among New 

 Zealand shells. I, however, think the South Australian shells 

 worthy of a name, but they should not be called A. cantharus, 

 Reeve. I therefore conclude, as Suter already has done, that 

 A. cantharus, Reeve, does not occur in Australia. 



Let us now consider the specific rank of A. cantharus, Reeve, 

 in New Zealand. Suter gives it full specific rank, but the study 

 of South Island shells does not warrant this. The characters 

 Suter uses for separating the two I have found to be of very 

 little value. 



The size of the shells depends a great deal upon their station. 

 A shell living in a secluded cavity, free from the action of rain, 

 may attain a large size, and does not suffer from erosion. In 

 the same locality shells living on boulders exposed to rain are 

 small and much eroded. These exposed shells never attain a 

 large size. I have cantharus much larger than Suter's measure- 

 ments — viz., 26 by 20 by 9 mm., 25 by 19 bv 9 mm., and 24 by 

 18 by 10 mm. 



The prominence of the radial striation is an inconstant 

 character, undoubted pileopsis having radial sculpture almost 

 microscopic. As eroded shells occur, this character could only 

 be used in conjunction with others. 



