448 Transactions. 



collection as regards these shells, and was astonished at my results. 1 

 had first collated all the generic, subgeneric, and sectional names proposed, 

 with the types given by their author or the next worker to select such. 

 Rissoa has had three types, named by three workers, and, whichever of these 

 be considered the genus-name, Rissoa must be eliminated from Neozelanic 

 literature. 



I now propose a scheme of nomination adapted to austral species, and 

 would urge its acceptance by austral students. It may seem at first arbi- 

 trary and in some ways inconsistent, but I believe it to be based on sound 

 principles. It is the result of consideration of European Rissoids, both 

 Recent and fossil, in conjunction with Australian, Neozelanic, and Lord 

 Howe, Norfolk Island, Kermadec, and Lifu species. I deliberately mention 

 these islands as I have many species from these groups, and these have 

 reinforced the opinions produced by the study of the Neozelanic species 

 alone. 



Suter has accepted the genus Rissoa, admitting six subgenera — Rissoa 

 (s. str.), Alvania, Onoba, Ceratia, Cingula, and Setia. As distinct genera he 

 includes Amphithalamus and Anabathron. 



More space than would be here allotted is required to record all the 

 vicissitudes of Rissoid classification as regards austral forms. . Here it 

 can be noted that Hedley (Zool. Results " Endeavour," pt. i, p. 105, 1911) 

 has rejected Rissoa, with type Turbo cimex L., as available for many 

 austral species, and has substituted Amphithalamus. I do not agree with 

 his association of species under the latter name, and these. I will hereafter 

 discuss. The type of Rissoa named by Hedley is the type of Alvania, so 

 that name must also be omitted from consideration in connection with 

 these species. The shell Suter names as type of Rissoa appears to have 

 the best claim, but that will be discussed fully elsewhere. 



Onoba, I conclude, can be used for certain Neozelanic shells without 

 recourse to animal characters. Ceratia would be also available, but it is 

 preoccupied. Cingula has no representative in New Zealand, whilst Setia 

 is also preoccupied. 



My scheme necessitates the introduction of new generic names for 

 austral groups, and I would at once protest against the action of some 

 conchologists who, without making any study of the subject, throw all 

 new names into synonymy. If these minutiae be carefully studied, I 

 prophesy the proposal of many more genera rather than the rejection of 

 the few I separate. 



Firstly, there is an austral group oscillating about Rissoa cheilostoma 

 Ten.-Woods. This group is well marked, and I have half a dozen distinct 

 species under review at the present time : these all agree in general ap- 

 pearance, in the spirally sculptured protoconch and the heavily varicosed 

 somewhat oval aperture, though varying from minute slender elongate forms 

 to large stout tightly wound forms. These have been classed in Alvania 

 and Alvinia, but examination of the type of Alvania shows a very different 

 style of shell. Alvinia recalls them, but species of that genus have a smooth 

 protoconch, and are different in texture, resembling that of Brookula. A 

 number of small shells with a smooth protoconch and a Brookula appearance 

 also occur in Australian waters, but these when compared with Alvinia 

 do not match at all, showing the great difficulty of judging " Rissoids " 

 from descriptions or figures. I will elaborate this group later, as I know no 

 Neozelanic species, though Rissoa pingue Webster, a species I am not 

 autoptically acquainted with, may belong here. 



