292 TAYLOR : VARIATION OF LIMN^A PEREGRA. 



Var. acronica Studer. Shell much longer than broad, spire excessively 

 short, last whorl shouldered, aperture oblong-oval. 



The original figure given by Charpentier 

 (Moll. Suisse, pi. ii., fig. 16) is to me con- 

 clusive that Moquin-Tandon is in error in 

 considering this as a variety of oiiricularia. 

 That accomplished conchologist, M. Bour- 

 guignat, however, also regards it as having 

 its afiinities more with aiiricularia than peregra, as he places it 

 in his group Auriculariana. 



Westerlund refers it to LimncBa tniiiida of Held as a variety. 



The specimen figured by me I owe to the kindness of Mr. 

 L. E. Adams, of Penistone, who gave it me amongst others 

 collected by him near Stafford. It differs from the type figure 

 in being a trifle more convex and less shouldered at the 

 aperture, but there is no other noticeable divergence. 



Var. lacustris Leach. "Shell resem'bling that of the last variety [var. 

 hiirneiti\ hn\. is much smaller and more glossy, 

 and has strong and regular transverse grooves, and 

 the spire is not quite so short, nor in.lined to be 

 intorted. The shell is often eroded." Jeft'icys, Brit. 

 Conch., I., p. 105, 1862. 



This is closely allied to the variety burnetti, but the tip of 

 the spire is not actually intorted, as in that variety. It is widely 

 distributed in more or less characteristic forms. 



Captain Brown's variety only seems to differ from that of 

 Leach by its greater delicacy and transparency, a circumstance 

 tliat has been attributed to its inhabiting the deeper parts of the 

 lakes where it is found. 



In Duddingston Loch near Edinburgh, Mr. W. D. Roebuck, 

 amongst a lot of the commoner form, found one specimen of 

 the most exquisite glassy transparency and delicacy, which 

 rivalled in those characters the finest examples of Amphipeplea 

 glnfifiosa, and which withotit a very severe scrutiny would be 

 referred to that species. The var. ghuialis of Dupuy would 

 seem to be correctly referred to the form named by Capt. Brown. 



J,C,, vi,, Jnn,, jSgi. 



