62 SUTER : NOTE ON TROPHON UMBILICATUS. 



The same author, in 1S96, ' jniblished a note upon Mitrrx um^'ilirafu-o, 

 T. W., in which he explains that Tryon proposed the name M. aivjasi 

 as a substitute for sca/ans, not knowing its identity with M.umhUicaiux, 

 and mentions tliat Brazier sent a specimen to H. Adams, who said it 

 was identical with that named M. Kcalaris by his brother. Dr. Verco 

 further gives a good figure of the shell (/. r. PI. vii, f. 4). 



Pritchard and Gatliff'^ in their " Catalogue of Marine Shells of 

 Victoria," reproduce part of the synonymy, and observe, "Considerable 

 confusion has surrounded this species of wrongful identifications, etc." 



This is about the curriculum vitae of the species. — Returning to 

 Mrs. Kenyon's note the following passage is difficult to understand : 

 " Murex udoijonu't, Q. and G. One very fine specimen, showing that 

 Mr. Brazier erred in considering M. odogomcs to be identical with M. 

 umhilicatm." AVhere Mr. Brazier does consider the two identical is 

 unfortunately not stated, but on reading the foregoing quotations Mrs. 

 Kenyon will, I hope, be convinced that Mr. Brazier took just an 

 opposite view. It was Mr. Bednall who took the view assigned to 

 Mr. Brazier. 



After comparing a good many examples from Hauraki Gulf, and 

 also a few from South Australia, I have come to the conclusion that 

 M. umhilicatu'i, T. Woods, is absolutely nothing more than a varietij of 

 i/. odogonus, Q. and G. I have a number of specimens of both 

 before me in which there is decidedly no other difference to be found, 

 but that in the var. umlnHcaia there is a more or less open umbilicus 

 present, which of course causes the spines round the base to spread 

 much further out. Mrs. Kenyon says that in M. odogonus the shell 

 is much more fusiform and turreted. I measured six specimens of 

 each and the result is as follows : In M. odogonus the proportion 

 of breadth to length was found to be i : i'8, and in the var. 

 unihillcata it varied from i : 17 to i : i"2i, the mean being i : i'S.< 



The sculpture in M. odogonus^ Q. and G., varies greatly according 

 to the locality and the depth in which the molluscs live. Shore 

 specimens in New Zealand average the size of my specimens from 

 South Australia, about 20-25 miHim. in length, but when we get 

 specimens from deeper water, say 10-20 fathoms, the shells are much 

 larger, up to 50 millim. in length. This also applies to the var. 

 umhilicata. The same conditions also influence the sculpture of the 

 shell. Deep water specimens are almost always beautifully ornamented 

 with prickly spines on the varices and round the base, but shore 



7 Ibid., 1S96, p. 231. 



8 Trans. Roy. Soc. Victoria, 1S98 (n.s.), vol. x, p. 254. 



