SMITH : ON BRITISH HYDROBI^. 143 



Frankfort. He informed me that he did not recognise it, and 

 that the most nearly allied species with which he was acquainted 

 was H. legrcindiana of Brazier from Tasmania. 



Through the liberality of Lieut. Beddome, the British 

 Museum possesses a series of eighteen specimens of this species 

 from near Hobart lown and Launceston. Although very closely 

 resembling the Plumstead species I think they may be regarded 

 as distinct. H.jenkinsi attains larger dimensions and the relative 

 proportions of the spire to the body-whorl is different. Mr. 

 Marshall, of Torquay, has also had examples of this same 

 Plumstead shell sent him by various correspondents and he has 

 very kindly allowed me to see his notes upon them which pre- 

 cede this paper. He is of opinion that they belong to Jeffreys' 

 var. ovata of H. ventrosa. As I have come to a different con- 

 clusion I thought it advisable that our opinions should appear 

 side by side, so that the probable correctness of either might be 

 the better estimated. Since sending the first batch of specimens, 

 Mr. Jenkins has been good enough to obtain for me living 

 examples of H. stmi/is, H. ventrosa from Erith, and also the 

 Plumstead form under discussion, and Mr. Crouch, braving the 

 wretchedness of a cold, damp, foggy Sunday morning, procured 

 living specimens of the last-mentioned from the ditches at Beeton. 



I kept all of these alive for some time and was able to make 

 drawings and prepare descriptions of their external features. I 

 may state at once that the appearance and habits of the animal 

 of the Plumstead-Beeton variety are perfectly different from 

 those of H. ventrosa and it certainly is not a variety ot that species. 

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

 have considered it a variety of that species. It much more 

 nearly resembles H. similis as regards the animal, but is not 

 absolutely the same, and conchologically the two forms are 

 certainly distinct. 



The only description of the animal of H. ventrosa which I 

 have been able to discover is that given by Jeffreys (Brit. Conch, 

 vol. i, p. 66). It is as follows: --"Body dark grey, almost black 



