434 Transactions. 



differential characters. Again, the British Museum classification is in agree- 

 ment with my own conclusion. The first reference is that in DieffenbachV 

 " Travels in New Zealand," vol. ii. p. 259. 1843. where the name is written 

 Tugali. I see with regard to both this reference and that of Clypidina 

 that Suter gives Syst. Dist. Moll. Brit. Mus., though quoting dates correctly 

 as 1843 and 1817 respectively. The book quoted did not appear until 

 1857. Such action is most confusing, as Suter gives the second reference 

 in his specific synonymy. 



ruder the genus-name Hemitonia Swainson, 1840, a series of shells is 

 arrayed in the British Museum (the genus-name Subemarginula not being 

 recognized) which can be easily divided into three groups. No intermedi- 

 ates occur in any way, so that these should be regarded as genera. 

 Examination of the radula will confirm this. The first group consists of 

 Patella octoradiata Gmelin alone, and for this Subemarginula Gray, 1847, 

 must be used. The second, typified by tricostata Swainson, must bear the 

 name Hemitoma Swainson, 1840. The names, in the British Museum, 

 associated with species congeneric with this shell are australis Quoy and 

 Gaimard, scidptilis A. Ad., panhi Quoy and Gaimard, panhiensis Reeve, 

 imbricata A. Ad., guadaloupensis Sowerby, polygonalis A. Ad., nodulosa 

 A. Ad., and oldhamiana G. and H. Nevill. Some of these may be synonyms, 

 and I simply quote them to show the extent of the group and the ease 

 with which species may be determined. To this genus must be assigned 

 Em marginata Blainville, but this specific name is generally aban- 



doned as indeterminable. I would observe that Blainville appears to have 

 previously described this specie- in the Diet. Sci. Nat. (Levrault). vol. xiv, 

 p. 382, 1819, under the name Emarginula subemarginata, but here also the 

 description is indeterminate. 



The third group is represented in the British Museum by shells bearing 

 the names rugosa Quoy and Gaimard ; Candida, anntdata, and stellata, all 

 of A. Adams; andfungina, aspera. radiata, and cinerea, all of Gould. Again, 

 these contain recognized synonyms, but probably other district species 

 could be added. This is the group occurring in the Neozelanic fauna, and 

 it was necessary to find a name for it. 



As a synonym of Subemarginula, Pilsbry included Siphonella Issel. but 

 on p. 284 he dismissed the species thus: " S. areonatii Issel (Mai. Mar. 

 Ross., p. 232). Unfigured. Gulf of Akaba." This was easy, but quite 

 unscientific, for on reference to Issel's work I find a long, careful description 

 given, and the group to which the shell belonged is easily determined by 

 the characters, " Testa solidiuscula, capuliformi . . . costis 3 anticis 

 productioribus, media maxima, intus laevi, canali profundo antice munita ; 

 apice subcentrali recurve."' Siphonella Issel, 1869, thus becomes a synonym 

 of Hemitou/a ; but the name is also preoccupied. As the name of a section, 

 Pilsbry used Plagiorhytis Fischer (Man. Conch., p. 860, 1885), and thereto 

 added only stellata A. Ad. and sulcifera A. Ad. When Fischer proposed 

 this name he regarded *S'. rugosa Quoy and Gaimard as typical of Sub- 

 emargimda Blainville, 1825 = Hemitoma Swainson, 1840 = Montjortia Recluz 

 1843 = Siphonella Issel, 1869. His definition of Plagiorhytis reads, " Rigole 

 oblique et dirigee un peu a, droite {S. stellata A. Adams)." It would seem, 

 then, that Fischer intended to name the " emarginata Blainville" group, 

 but the species named is referable to the " rugosa " group. Neither Fischer 

 nor Pilsbry had ever seen Adams's types of stellata. Fortunately we are 

 relieved from the decision of fixing Fischer's name, as it is invalid, being 

 preoccupied. In the synonymy Fischer has given " Montjortia Recluz, 



