70 LIMN^EID^E. 



substances, to which it adheres very firmly ; occa- 

 sionally, but rarely, it may be seen on the under side 

 of the leaves of aquatic plants, and sometimes it 

 leaves the water altogether for a time and crawls up 

 moist rocks or wooden piles. It lays about eighty 

 eggs during the breeding season ; they are deposited 

 in from seven to ten amber-coloured capsules, and 

 the fry are excluded after the lapse of twenty-four 

 to twenty-seven days. 



Var. i. Capuloides. Shell larger and higher, with the beak 

 not placed so near the posterior margin. Very rare (J. G. J.), 

 B.C. Near Birmingham (G. Sherriff Tye), near Wakefield (J. 

 Hebden), J.C. I found a single specimen on the under side of 

 a leaf of the water-lily in the River Colne near Colchester. 



Var. 2. gibbosa. Shell smaller, more swollen, with the beak 

 reaching or overhanging the posterior margin. Sark, Os- 

 mington Mills near Ringstead, Dorset, Dunboy near Bear- 

 haven, Co. Cork (J. G. J.), B.C. Near Leeds (W. Nelson), 

 Yorkshire, two localities (H. Crowther), J.C. 



Var. 3. albida. Shell milk-white, and more finely striated. 

 Various localities. 



In the ' Annals and Magazine of Nat Hist' for 

 October 1876, Mr. E. Duprey, in a paper on some of 

 the Mollusca of Jersey, makes the following remarks 

 respecting A. fluviatilis : "More than once I have 

 found young specimens of this slow animal adhering 

 to an active flying water-beetle, the Acilius sulcatus. 

 Thus carried from one pond to another, it can be 

 rapidly distributed throughout the country." 



How truly admirable as well as endless are the 

 means by which Nature provides for the distribution 

 of her works ! 



