LIMN&A. 53 



cleverest human gymnast that ever performed. I 

 once saw one ascending, and when it was half-way 

 up the thread it was overtaken by another ; then 

 came the 'tug of war.' Each tried to shake the 

 other off by repeated blows and jerks of its shell, at 

 the same time creeping over each other's shell and 

 body in the most excited manner. Neither being 

 able to gain the mastery, one began to descend, fol- 

 lowed by the other, which overtook it, reaching the 

 bottom first. Yet they are not always bent upon 

 war, but pass and repass each other in an amicable 

 spirit." 



The gelatinous capsules of P. fontinalis contain 

 from five to twenty eggs. The fry are excluded at 

 the end of about twenty days. 



Var. i. inflata. Shell half as large again as the usual size ; 

 whorls angular towards the suture, the middle one rather more 

 prominent than the penultimate whorl, causing the summit of 

 the spire to appear abruptly terminated. Dublin (Humphreys 

 and Warren), B.C. Near Birmingham (G. Sherriff Tye), J.C. 



Var. 2. curta. Spire extremely short. Clonoony Barracks, 

 Ireland (Brown), Bramerton, Norfolk (J. G. J.), B.C. Perth- 

 shire (Buchanan White), S. N., vol. ii. p. 207. 



Var. 3. oblonga Spire considerably produced. Anglesea 

 (J. de C. Sowerby), Naas, Ireland (Humphreys), B.C. River 

 Went, Yorkshire (J. Hebden), near Birmingham (G. Sherriff 

 Tye), J.C. 



Var. 4. 'albino,. Shell of a milk-white colour. Birkenhead 

 (Webster), B.C. 



GENUS III.LIMN&'A* (LYMNEA\ BRUGUIERE. 



Body longish, spiral ; mantle entire ; tentacles rlattish, sub- 

 triangular, short ; foot strongly notched in front, obtuse behind, 



* Inhabiting marshy places. 



