312 ON THE GENUS PERRIERIA, 



Adams and Angas show no intention of suppressing their genus, 

 but merely offer a modification of it. If they had deliberately 

 made the alteration imputed to them by Fischer, such an illegal 

 procedure could not be tolerated. 



An examination of the figures and description (P.Z.S. 1867, p. 

 907, pi. XLiii. figs. 16, 17) of G. exigua has satisfied me that the 

 authors of that species had before them no Solomon Island shell, 

 but the Queensland (P.) australis, Forbes. My colleague Mr. 

 Brazier, who at my request compared the Australian shell with 

 the figures and description in question, quite supports this identi- 

 fication. C. exigua may therefore be considered an absolute 

 synonym of C. australis, and the habitat assigned to the former 

 to be erroneous. 



So manifold are the difierences between layardi and australis 

 that no zoologist will be hardy enough to confine the two within 

 the limits of a single genus. Coeliaxis being appropriated to 

 layardi, another genus must be found for the reception of 

 aicstralis. It will not, however, be necessary to invent one. In 

 the "Comptes-rendus de I'Acad. des Sciences," Vol. Ixxxvi. 1878, 

 p. 1150, Tapparone-Ganefri thus defined the genus Perrieria: — • 

 " Testa sinistrorsa, f usiformis, multispira, apice truncata ; aper- 

 tura elliptica ; peristoma continuum expansum ; axis sinuosus, 

 basi contortus et columellam truncatam atque subdentatam simu- 

 lans." A single species, clausiliaeforynis, Tapparone-Canefri, from 

 Port Dorey and Mount Arfak, Dutch New Guinea, furnished the 

 above generalisation, which with the exception of " sinistrorsa " 

 perfectly agrees with the Australian representative. So many 

 genera, Partula, Pujja, Clausilia, for example, are indifferently 

 dextral or sinistral, the indifference even extending to species, 

 that slight importance can be attached to this feature. With 

 the admission of the second species, australis, the definition of 

 Perrieria will therefore require motlification in this particular. 



As Nevill points out in the "Hand List of Mollusca in the 

 Indian Museum," p. QS, Crosse and Fischer have been most lax 

 in the matter of types ; Fischer's " Manuel de Conchyliologie," in 

 the main a very useful work, contains many errors of this 



