76 THE DISPERSAL OF SHELLS. 



would be thought to be considerable ; ^ and climbing 

 powers are possessed also, both by frogs and toads, which 

 can surmount small barriers of many kinds, but a shell 

 upon one of the toes, though not usually much impeding 

 ordinary progression, might seriously hinder the animals 

 when climbing.- Mr. Peers remarked, in 1865, that a 

 bivalve by clinging to an amphibian ''acquires a more 

 rapid and extended locomotion than it possesses of 

 itself, which perhaps may be a means of its distribution," ' 

 and in all probability he was right, for, from general 

 considerations, it seems in the highest degree probable 

 that such creatures occasionally carry shells from pool 

 to pool, or from swamps and marshes adjoining rivers 

 to ponds more or less remote and isolated, but I have 

 not heard of their having been found, with shells 

 attached, at any great distance from water. Three 

 cases, which I have kept back, however, are of some 

 significance. In 1886, a newt, with a shell oi Sphcerium 

 corneum upon its right fore foot, was discovered by Mr. 

 Hardy at the base of a wall at Dunham Massey, 

 Cheshire, between the grass and the wall, and about 

 ten yards from the water of a small pond, which it 

 appeared to have left : a frog, with a shell of the same 

 kind upon one of its toes, was once found by Mr. 

 Standen undera log in a damp ditch about thirty yards 



^ Darwin, "Nature," xxv. (1882), 529-30. 



^ As to the climbing powers of frocks and toads, see " Science 

 Gossip," 1867, p. 234 ; 1868, p. 94; xvi. (1880), 23, 64, and 165 ; 

 xvij. (1881), 69; xviii. (1882), 215 ; "Zoologist,'' xxi. (1863), 8861 ; 

 xxii. (1864), 8927 ; (2), iv. (1869), 1830 ; (3), i. (1877), 184. 



2 J. Peers, "Zoologist," xxiii. (1865), 9697-8. 



