Iredale. — Sitter's "Manual of the New Zealand Mollusca." 429 



are quoted by Suter for A. helmsi — viz., Greymouth and Cape Egmont. 

 Examination of the types, however, show it to be a common shell occur- 

 ring at manv points from Lyttelton to Dunedin, and which I had so 

 identified, but ranked as a variety of A. septiformis Q. & G. I would 

 reject this latter from the Neozelanic list, as it seems to be the Australian 

 representative of the Neozelanic A. pileopsis Quoy and Gaimard. The two 

 species seem liable to extraordinary variation, due to environmental stresses, 

 and really many well -differentiated forms should be recognized in both 

 species. The Australian septiformis runs into the form called " cantharus," 

 quite wrongly according to my investigations ; and at Caloundra, Queens- 

 land, I collected two fine shells which immediately recalled large pileopsis : 

 they were less elevated, more rounded in outline, and rayed with white 

 rather than spotted ; internally they showed the same black edging and 

 light inside coloration. If the Neozelanic and Australian forms be con- 

 sidered separately, and the variation of each carefully studied, much more 

 good would be effected. It does not seem possible with the present material 

 to class helmsi as a variant of pileopsis, so that a good deal of collecting 

 must be done before much advance can be made in this family. One point 

 I would emphasize is that, from any given place, series of these shells are 

 fairly constant according to their environment. 



Notoacmea pileopsis (Quoy and Gaimard, 1834). [P. 71.] 



Through usage of alphabetical sequence Acmaea cantharus (Reeve) 

 appears five pages away from Acmaea pileopsis (Q. & G.). In life there 

 is no such separation. My conclusions put forward in Trans. N.Z. Inst., 

 vol. xi, p. 367, 1908, regarding the identity of these two are therefore not 

 accepted. Further study has not occasioned the revision of my facts, 

 and I would note that since I wrote I have seen that Pilsbry (" Nautilus," 

 vol. viii, p. 127, 1895) had recognized the Tasmanian shell as the true 

 cantharus Reeve, quoting that Hutton had previously so decided. Pilsbry, 

 however, has never seen Reeve's types, which I have now examined, and 

 I find they are undoubtedly the Neozelanic shell upon which my con- 

 clusions were framed. I had thought that it might be possible to rank 

 cantharus Reeve as the southern geographical representative of the northern 

 pileopsis. I find that this is impossible, as, though Quoy and Gaimard 

 gave as localities Bay of Islands and French Pass, they described and 

 figured a shell quite like cantharus. Suter's recognition of both species at 

 the Auckland Islands necessitates the rejection of specific distinction; and, 

 finally, the name cantharus is predated. 



Patella sturnus Hombron and Jacquinot (Ann. Sci. Nat., 2nd ser., vol. xvi, 

 p. 191, 1841) refers to this species, and as the description applies to the 

 cantharus form, and the type was almost certainly collected in Otago, 

 where cantharus is abundant, it would have to come into use. It is some- 

 what remarkable that, while this name passed into the synonymy of P. 

 radians Gmelin, the succeeding Patelloides antarctica was correctly placed 

 under the present species. 



Patella floccata Reeve. [P. 71.] 

 This name has continually given trouble, and its last resting-place is 

 in the synonymy of Acmaea pileopsis Q. & G. I have carefully examined 

 the types of this species, and would suggest it is not a New Zealand shell 

 at all. It is not, from shell characters, an "Acmaea " at all, but belongs 

 to the familv Patellidae. 



