124 ^^"'' ^^i^^i' Naturalist. Aug.-Sept., 



exceedingly nervous excitable mollusc, crawling actively 

 about and frequently loosening its hold and floating to the 

 surface, where it coasts about with its foot uppermost. 

 1 have often noticed this habit in L. peveger, but not to 

 the same extent as in L. praetemiis. The latter mollusc 

 is so sensitive that if a shadow come across the sun many 

 individuals immediately retire beneath the stones, and if 

 the sunHght fall on a spot hitherto shaded by the high 

 rocks which surround a tarn specimens come crawling out 

 in all directions where few were visible five minutes before. 

 The difference in the habits of L. praetenuis and L. involuta 

 has already been noticed by Fleet-Surgeon K. H. JonesJ 

 but in his case the more active mollusc was seen climbing 

 on weed in Lough Nagarriva, whereas there are few or no 

 weeds in the Caha Lakes. I noticed one other point that 

 may prove of interest ; on reaching home I found that L. 

 pereger had usually withdrawn far into its shell, L. praetenuis 

 just to the lip, and L. involuta had rarely wholly retired. 

 I do not, however, regard this difference in the habits of 

 the three as being of more than racial importance, any 

 more than I regard the different habits of the trout in the 

 various lakes as any claim to specific rank ; in one lake 

 the trout will rise furiously to fly while in the next it will 

 be useless to fish for them except with worm on a dull day. 

 The following is a complete list of the lakes I have 

 visited round Glengarriff and of the Limnaeae inhabiting 

 them ; the heights are approximate, to the nearest 50 feet, 

 for as can be seen from my description of the flow of the 

 streams there are slight differences in the height of almost 

 all of them. ^ 



Barley Lake, Caha range, 779 feet, contains L. involuta, 

 , where it was discovered by Mr. R. A. PhiUips some 



years back ; it is not of such an extreme form as those 



from Lough Crincaum, Killarney. A few specimens 



have rudimentary spires. 

 Lough " A," Caha Lakes, 1,400 feet. — L. praetenuis, all 



extremely short-spired, quite fifty per cent, of the 



specimens being more or less intorted. 



^Journal of Conchology J vol. 13, p. 288. 



