88 PEOCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



Cooke, in 1889 (Proc. Zool. Soc. Lond., 1889, pp. 136-43), dis- 

 cussing the sinistral shells from Australia that had been referred 

 to Physa, concluded that they were, judging by the radula, 

 generically identical with Isidora, and, evidently unaware of the 

 history of the name detailed above, followed Fischer in accepting 

 Adanson's Bulinus for them. In 1895, however (Cambridge Nat. 

 Hist., iii), Cooke abandoned the name Bulinus in favour of Isidora. 

 He seems to have overlooked the fact that Adams' name Ameria, 

 were his conclusions correct, would have priority. 



A comparison of Jickeli's figures of the radulae of Isidora, on 

 which Cooke relied, with those which the latter author gave of the 

 Australian shells shows the existence of certain differences which 

 lead us to think that he would nowadays be disposed to consider 

 sufficient to differentiate the Australian physoids from Isidora, and 

 as he pointed out that though Adams founded this Ameria on 

 keeled examples " every gradation of keeling is observable . . . and 

 occasionally the same species is indifferently keeled or perfectly 

 smooth ", would further be disposed to accept Adams' name for 

 the Antipodean shells, whilst we are not sure but that he would 

 separate off the New Zealand from the Australian^forms. All this 

 Dr. Cooke now assures us in a recent letter is in effect the case. 



Tate in 1896 (Rept. Horn Exped. Centr. Austral., ii, p. 212) 

 proposed the name Isidorella for certain other Australian physoid 

 forms allied to the Physa newcombi. Ad. & Aug., in which there 

 is no columellar fold. 



Our conclusions, therefore, are : that the only group to which 

 the name Bulinus could have been correctly applied would have been 

 to that which bears, and should retain, the name of Physa ; that 

 the Egyptian shells which play the part of host to Bilharzia should 

 be known as Isidora ; that their Australian kindred should retain 

 the names Ameria and Isidorella, the New Zealand offshoot receiving 

 a fresh name ; whilst the fossil Physa prinsepii, Sowb., which 

 Annandale has lately referred to Bullinus (Journ. and Proc. Asiatic 

 Soc. Bengal, n.s., xvi, 1920, p. xxiv) is most likely a distinct type.^ 



ViVIPARUS. 



The occurrence in the Linnean Collection of the numbered 

 specimens of his Helix vivipara and the receipt from Dr. Johansen 

 of plesiotypes of Miiller's Helix fasciata has put the identity and 

 nomenclature of the two British species beyond question. 



How it came about that for a time there was considerable confusion, 

 and its probable explanation, is, however, of interest, and we think 



^ Dr. Annandale writes ; " From a purely technical point of view I agree 

 that Isidora is preferable to both Bullinus and Bulinus, but Bullinus has 

 obtained currency in medical literature, and I regard it as a nomen 

 conservandum." Thus does error seek ever to justify itself ! 



