142 LIMNJEADJE. 



ginated ; its edge not sinuated, advancing above, receding 

 below. Columella white, narrow, only a little twisted, 

 forming an obtuse angle by its comparative straightness 

 with the obliquely arcuated upper outline of the inner lip. 

 No vestige of an umbilical chink. Size of a large indi- 

 vidual one-third of an inch long, nearly a quarter of an 

 inch broad. The variety acuta is larger, with the spire 

 more elongated, so that the aperture fills only two-thirds 

 of the ventral length. 



The rare long spired variety (f. 10), may possibly 

 prove a distinct species, and, assuredly, differs as much 

 from the typical form as many of the supposed species of 

 Pht/sce do from each other. Yet in that event, we should 

 be unable to allocate those examples of fontinalis which 

 only differ from the type by the greater projection of their 

 spire. * It is the shell represented by Maton and Rackett, 

 in the Linnean Transactions (vol. viii., pi. 4, f. 1), as B. 

 fontinalis, and is the PJiysa fontinalis, var. 1, of Gray 

 (Manual L. and F. W. Shells, p. 251, pi. 11, f. 110, 

 a), and, in all probability, the same species, var. 2, of 

 Brown,f), III. Conch. G. B., p. SO, pi. 14, f. 83, 84. 

 It is a narrower shell than the typical form, is more 

 obliquely coiled, and, consequently, has a more produced 



* The following observation of Mr. Gray, in his excellent edition of Turton's 

 " Manual," merits the attention of every naturalist : — " Mr. Hindi informs me, 

 the first variety is always found in very small plashes of water, or in water 

 among grass, while the larger one is found in canals or nearly still rivers, which 

 may account for the difference between them; for we have often been inclined to 

 consider varieties as distinct, because they were found in different situations, 

 wJtereas the differ* nee of situation may be the only cause of the variation.' 1 '' 



t Not his P. acuta, pi. 14, f. 58, 59, which is copied from Draparnaud (Moll. 

 France, pi. 3, f. 10, 11), and has an acute apex and very short spire (p. 30). We 

 have no proofs that that species has ever been found in Great Britain. The 

 erroneous introduction of it occurred through the supposed identity of the ex- 

 amples queried for acuta by Mr. J. Sowerby (one of whose specimens we have 

 figured, with the true P. acuta of the French conchologist. 



