114 Proceedings of the Royal Society of Victoria. 



that the form desci-ibed by Professor Tate under the name of 

 T. warburtoni is intermediate between those described by Teni- 

 son Woods under the names of T. warburtoni and T. siurtii, 

 the latter being characterised by Tenison "Woods in the matter of 

 ornament as follows : — " The three prominent ribs on the whorls 

 are all granular, the larger two at the base of the whorl, and the 

 third above and separated by a wide interval in which smaller 

 ribs occur." Again, Professor Tate's description of T. siurtii 

 differs from the original of T. Woods in that he remarks : — 

 "Prominent ribs three, equidistant, of which the median and 

 anterior ones are granulose, the posterior one often double, each 

 interspace with about two fine spiral threads." 



From the above remarks it can be readily seen that there is 

 considerable variation in the ornamentation of these Turritellas, 

 and Professor Tate's redescriptions of T. Woods' species, together 

 with my own observations on a very large number of specimens 

 (upwards of 150), constrains me to the belief that we are merely 

 dealing with an extremely variable form, which would be better 

 designated by the one name, T. -ivarbiirtoni, T. Woods, than by 

 an indefinite multiplication of species. The extreme difference 

 in shape to which this species is subject is fairly well represented 

 Ijy Pi-ofessor Tate's figures to Gastropoda, Part IV., pi. viii., 

 figs. 2, 2rt, 2<^, and 6, 6^, 6/;, l)ut in a large series intermediate 

 forms are not uncommon. 



The apex is described by Professor Tate as consisting of " two- 

 and-a-half smooth turns " in the one case (7^ warburtoni') and 

 "three small, smooth, rounded turns " in the other (Z! sturtii). 

 We are unable to compare this part of the description with that 

 of T. Woods, as he simply says, in both instances, " apex always 

 decollated." 



As the specimens described by T. Woods under both these 

 specific names were evidently imperfect examples, I cannot gain 

 any reliable information as to the number of whorls. Professor 

 Tate, however, states that T. warburtoni has fifteen whorls in a 

 length of 9 '5 mm., while T. sturtii has the same number of 

 whorls in 12 mm. In my examination of apically perfect speci- 

 mens I find considerable variation in the nundjer of whorls in a 

 definite length, and as would naturally be expected, the more 

 acute varieties are those which possess the greatest number of 



