2 24 JOURNAL OF CONCHOLOGY, 



FURTHER NOTES ON BRITISH HYDROBI^. 



By J. T. MARSHALL, 



In Mr. Edgar Smith's "Notes on Hydrobiae," following 

 mine, in the last number of the Journal, he proposes that the 

 shell hitherto known as H. ventrosa var. ovata should be raised 

 to the rank of a species as H. jenki7isi, on the ground that the 

 animal is "perfectly different" from the type, and that "Jeffreys 

 never could have seen the living animal or he would not have 

 considered it a variety of that species." 



Although I have collected the shells, I have taken Jeffreys 

 for granted and have not examined the animal ; but I am quite 

 content to consider it either a species {H. jenkinsi) or a variety 

 (^H. ventrosa var. ovata). 



Before doing so, however, I should like to point out that 

 although Mr. Smith gives four propositions to show its claim to 

 specific rank, three are clearly varietal, one only ("length and 

 form of tentacles ") being what I should call specific ; and this 

 one would be sufficient for me were it not that Mr. Smith's 

 amended descriptions, both of ^. ventrosa and H. similis, differ 

 from Jeffreys' usually careful and succinct diagnoses, even in 

 some important respects. 



There can be no doubt that Jeffreys had this shell before 

 him when he described his var. ovata., as the characters of the 

 suggested H. jenkinsi are absolutely identical with his detailed 

 description ; moreover, with a series of specimens from different 

 localities typical H. ventrosa can be graduated with the greatest 

 ease into that of H. jenkinsi. 



I therefore consider that further examination is desirable 

 before H. jenkinsi can be pronounced specific. 



With regard to Frauenfeld's statement that our H. similis is 

 a Bithynia, there must be some error. The Cyclostoma simile 

 of Draparnaud is certainly a synonym of our shell, and 

 if the latter's type in the Vienna Museum has the concentric 



J.C, vi., Apr. iSgo. 



