FAMILY PHYSID^E 1 05 



arcuated, thin, cartilaginous, without accessory plates ; other charac- 

 ters as in Physa. 

 Type Bulla hypnorum Linne, 1758, Holarctic. 



The nomenclature of this genus has been subject to some vicissi- 

 tudes. In 1757 Adanson, who did not adopt the binomial nomencla- 

 ture, described a minute shell from the fresh waters of Senegal under 

 the name of " le Bulin, Bztlinus." From its form and size it was 

 certainly not an Aplexa, but rather a species of the group called by 

 Ehrenberg, in 1831, Isidora. This genus has the jaw and radula of a 

 Planorbis and may be regarded as a physiform relation of the latter 

 genus. To a considerable extent it replaces Physa in tropical 

 Africa. 



Scopoli in 1777 attempted to utilize Adanson's researches, and 

 proposed a genus JBulimus in which he included Limncza, Succz'nea 

 and Bythinia (sp.), attributing the genus to Adanson and paraphras- 

 ing Adanson's diagnosis of the characters of the animal. The name 

 was later used for the large land shells for which it is familiar, but to 

 which the diagnosis cannot be applied. 



It seems almost certain that Bulimus (Scopoli) is a misprint for 

 Bulinus (Adanson), but, as usual, several authors have not hesitated 

 to propose a bogus derivation for a name for which the author gave 

 no derivation, and have ignored the statement of Adanson, who gives 

 a legitimate and totally different source for the name. 



However this may be, Bulimus long had currency in concho- 

 logical nomenclature for animals with which we are not here con- 

 cerned, and in 1781 Otho Friedrich Miiller revived Adanson's name 

 in its original form for the group named Physa by Draparnaud 

 twenty years later. Miiller included in his list of species Adanson's 

 type (to which he gave the binomial name Bulinus Senegal ensis}, 

 Bidinus turritus ( = Aplexa hypnorum L. sp.) and Bulinus perla 

 (= Physa fontinalis Drap.) . 



Since he states that his genus is that of Adanson, it follows that 

 Adanson's sole species must be taken as the type, which eliminates one 

 of the three groups concerned. For the group represented by Physa 

 fontinalis Draparnaud's name has been generally and properly 

 retained, while the first available name for the third group is Aplexa 

 Fleming. This is accepted and defined by Sowerby as indicated in the 

 synonymy above given, but may have been used earlier in print by 

 Fleming; though I have found no record of it if this be the case. 

 Sowerby speaks of it as if it were not a manuscript name, but does not 

 explicitly so state. 



