84 THE PROCEEDINGS OF THE LINNEAN SOCIETY 



genera included under this name but it was probably adopted 

 from Adanson (Hist. Nat. du Senegal. Goquillages. Paris 1757), 

 and included Limnea, Bithynia, and Succinea. It is now restricted 

 to ovo- viviparous land shells, oblong and turretted in form, and 

 with the longitudinal margins unequal, toothless, or dentate, 

 columella entire, revolute externally, or nearly simple^; peristome 

 simple or expanded. The species are very numerous, and they 

 are divided into many genera and subgenera by various authors. 

 Some copy the etymology of Adanson and write " Bulinus,^^ but 

 Messrs. Adams restrict this to fluviatile shells as probably its 

 author intended, and they define their Bulimus thus ; " Shell 

 solid sub-imperforate, or with the perforation covered, oval, or 

 ovately oblong, last whorl ventricose equalling the spire; aperture 

 oblong oval, columella rather straight, rarely plicate ; peristome 

 thick, expanded, reflected and sometimes arcuate, the margins 

 joined by a callus, the columella dilated, reflected.*" They thus 

 restrict thagenus to those species proper to tropical America. They 

 make a genus named Placostylus which they derive from Beckf 

 in which they place imperforate shells, oblong-conic, rugosely 

 striated, last whorl a little shorter than the spire, aperture oblong, 

 oval, or irregular ; columella tortuous, arcuately plicate, peristome 

 thick, reflexly expanded, the margins united by a shining tuber- 

 culated callus, the columellar (margin ?) dilated, appressedj." 

 The genus would seem to come very close to Auricula in ap- 

 pearance. Its geographical range according to the authors is the 

 Australian Islands, New Caledonia, and Australia. But none of 

 the species enumerated by the authors occur in Australia. The 

 sub-genus Gary odes, Albers,|| was adopted by them from the 

 author just named, for solid imperforate oblong oval shells with 

 plaits at the suture, the last whorl equalling the spire, a rather 

 straight columella and a simple obtuse peristome. They include 

 in this section Bulimus Baconi Benson (Ann. Nat. Hist., vol. 13, 

 p. 19, 1854) and B. Dufresnii. Dr. Cox, in his Monograph of 

 Australian Land Shells,^ very properly removes B. Baconi from 



* Genera of Recent Mollusca, vol. 2, p. 146. 



t Index. Mollusc. Principis Christ. Frederici, 4t-to, Hafn., 1837. 



I Adams loc. cit., p. 153, pi. 75, fig. 5. 



II Heliceen, Albers, Leipzic, 1860, 2nd edit., p. 228, Genus Buliminus. § P. 73. 



