CANTHARIDUS. 121 



to recognize a radula of this genus at a glance. The inner lateral 

 is slender, narrowed toward the cusp, like the centrals, and (some- 

 times at any rate) bearing a lamella behind the peduncle. The 

 outer laterals are very broad, with one or several denticles on the 

 cusp. Phasianotrochus (Elenchus of authors) has essentially the 

 same arrangement, except that the centrals lack the peculiar wings 

 to the peduncle (pi. 50, fig. 15, C. badius Wood). The radulse of 

 Thalotia, Odontotrochus and Bankivia are unknown. Watson says 

 that Leiopyrga has the same dentition as Margarita, but this must 

 be a mistake. 



The genus should be grouped with Gibbula in a natural arrange- 

 ment of the family. The only character separating Cantharidus from 

 that genus is the simple cusp of the central tooth, whilst in Gibbula 

 it is denticulate at the sides. [ am wholly inclined to disregard the 

 subfamily limits adopted in the first part of this work, (p. 6), and 

 even more those used by Fischer (Manuel, p. 817). But I do not 

 believe much improvement can be made until we have more knowl- 

 edge of the soft parts of Trochidse. 



In conclusion, there is no character of importance at present 

 known to me which will separate the small shining Australasian 

 Gibbula (such as picturata Ad. & Aug., nitida Ad. & Ang., fnl- 

 niinata Button, etc.) from the smaller species of Cantharidus; and 

 the resemblance between Cantharidus and Calliostoma, shown in the 

 shells of certain species, is no evidence whatever of relationship 

 unless Thalotia and Odontotrochus prove to have a very different 

 dentition from Cantharidus, in which event the genus will have to 

 be dismembered. 



The dentition of the following species has been figured by Prof. 

 Button (Trans. N. Z. Institute, xv, xiv ; 1881-'82). Cantharidus 

 purpuratus Mart., tenebrosus Ad., pupillus Gld. These figures do 

 not show as many teeth as is desirable. The only other radula 

 figured is that of C. badius Wood, by Troschel (Das Gebiss, ii, t. 

 xxiv, f. 4). 



As to the nomenclature adopted, Elenchus of Swainson is a 

 synonym of Cantharidus Montf. Elenchus of B. and A. Adams is 

 the same as Phasianotrochus Fischer, but not Elenchus (Bumph.) 

 Sw 7 ainson. I do not have access to the "Museum Calonnianum," a 

 very rare work in which Elenchus was proposed by Bumph rev ; and 

 do not know whether the genus was properly characterized or not. 

 The name was unknown in conchological literature until Swainson 



