152 The Irish Naturalist. 



Genus —PL ANORBIS. 



Planorbis corneus, L. 

 I? — III. — V. VL — — — — — — 



The largest Irish species of Planorbis, this is also one of the rarest, and 

 inhabits a comparatively small tract in central Ireland. The Dingle 

 record, mentioned by Thompson (15), has not been confirmed, and re- 

 mains doubtful. 



Fore;ign Distribution. — England, south Scandinavia, Russia, Tran- 

 S3'lvania, Austria, Germany, France, north Italy, Corsica, and west 

 Siberia. 



Planorbis marginatus, Drap. 

 I. II. — — V. VI. VII. — — X, XI. XII. 



This has a much wider distribution in Ireland than the last, but 

 becomes rarer in the west. It is probably PL umbilicatus of Muller and 

 Thompson. 



Fore;ign Distribution. — Great Britain, south Scandinavia, Finland, 

 Russia, Transylvania, Austria, Switzerland, Germany, Ital}^, Sicily, 

 France, Spain, Portugal, Algiers, Morocco, and west Siberia. 



Planorbis carinatus, Muller. 

 I. II. III. — V. VI. VII. — — X. — XII. 



As Thompson (15) has already mentioned, this species is muchless 

 common than the preceding. It frequents the same localities, viz : — 

 stagnant waters. 



Foreign Distribution. — Great Britain, south Scandinavia, Germany, 

 Austria, Switzerland, France, north Italy, Spain, and Portugal. 



Planorbis vortex, L. 

 I.? — — — V. VI. VII. — — X. — — 



The record by Humphreys (7) seems to me doubtfully referable to this 

 species, and although Thompson (15) considered it generally distributed, 

 our present knowledge of the distribution does not warrant such a belief. 



Foreign Distribution. — Great Britain, south Scandinavia, Finland, 

 Russia, Transylvania, Austria, Switzerland, Germany, Italy, France, and 

 Siberia. 



Planorbis spirorbis, Iv. 



I. II. III. IV. V. VI. VII. — IX. — — XII. 



This is one of the most generally distributed species of Planorbis in 

 Ireland. 



Foreign Distribution. — Great Britain, south Scandinavia, Finland, 

 Russia, Transylvania, Austria, Switzerland, Italy, Germany, France, 

 Spain, Portugal, Algiers, and Morocco. 



Planorbis contortus, L. 



I. II. — — V. VI. VII. VIII. IX. — XI. XII. 



I/ike the last, this may be looked upon as generally distributed over 

 Ireland. 



Foreign DIvSTribuTion. — Great Britain, Scandinavia, Finland, 

 Russia, Trans3'lvania, Austria, Germany, Switzerland, Italy, France, 

 Spain, Portugal, Siberia, and Kanischatka. 



Planorbis albus, Muller. 

 I. II. — _ V. — VII. VIII. IX X. XI. XII. 

 According to Thompson (15) this species prevails generally over Ireland. 



