MADEIRAN GROUP. 273 



Genus 19. PHYSA, Draj). 



Physa acuta. 



Physa acuta, Drap., Hist. Kat. o5. t. 3. f. 10, 11 (1805) 

 „ fontinalis, Paiva [nee Linn.'], Mon. Moll. Mad. 147 



(1867) 

 „ acuta, Watson, Joiirn. de Conch. 224 (1876) 



Habitat Maderam ; in aquis juxta Funchal, plantis aquaticis 

 adhserens. Certe ex Europa introducta. 



A Physa, of extreme variability as regards size, which 

 appears to have been introduced during- the last few years into 

 Madeira, occm-ring abundantly in the tanks and streams around 

 Funchal, — not merely in the towTi itself, but also in the Ribeira 

 dos Soccoridos, the Ribeira de Gonpalo Ayres, &c. ; but one which 

 seems to me to have been wrongly identified by the Baron Paiva 

 with the common European P. fontinalis, Linn. Mr. Lowe, how- 

 ever, in a paper which was published in the ' Annals of Natural 

 History' in 1862, says that 'in degree of ventricosity it is 

 intermediate between the P. acuta, Drap., and the more elon- 

 gated or slenderer Canarian shell so called by Webb.' This 

 latter has since been characterized by ]Mousson under the name 

 of ' P. tenerifce ;' though my own belief is that both it and the 

 Madeiran species are nothing more than very slight geogra- 

 phical phases of the common P. acuta. 



Genus 20. PLANORBIS, Midi. 



Planorbis glaber. 



Planorbis glaber, Jeffr., Trans. Linn. Soc. Lond. xvi. 387 

 „ laevis, Alder, Trans. Xeiucast. ii. 337 

 „ glaber, Paiva, Mon. Moll. Mad. 149 (1867) 

 „ „ Watson, Journ. de Conch. 224 (1876) 



Habitat Maderam ; ad fontes rivulosque circa Funchal. 

 Sine dubio introductus. 



This little European Planorbis has (like the Physa acuta) 

 established itself, during the last few years, in the streams and 

 cisterns around Funchal, — where it was first met with by Mr. 

 J. Y. Johnson in a tank in Dr. Lister's garden, and where it was 

 afterwards found (in the same spot) by the late Mr. E. Leacock. 

 Mr. Lowe, in adverting to some examples which had been sent 

 to him by the latter, remarks ('Ann. Nat. Hist.' for July 1860) 

 that they ' belong unquestionably to the P. f/laber, Jeffr, 

 [ = l(evis, Alder) ; and (like the H. aspersa, Miill., in another 

 garden at Funchal) the species has been doubtless introduced 

 within the last few years from Portugal, — where Dr. Bocage, 



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