MEANS OF DISPERSAL. 133 



directions by rock-snails [Helix lapicidd), great numbers 

 of which, of various sizes, were exposed to view when 

 the bark and portions of the wood were torn away/ 

 Species in no sense arboreal may often take up their 

 abode in chinks in logs which happen to be lying on 

 the ground on the banks of water-courses, and which of 

 course are liable to be drifted off during floods. 

 Strictly ground species may occasionally be carried, in 

 numbers^ in the earth, etc., at the roots of trees. It 

 seems probable also that many may be transported 

 with miscellaneous vegetable debris, cocoanut-husks, 

 etc., which must often be swept from the ground and 

 carried awa}^ to considerable distances, but snails 

 travelling in this way would be much exposed to the 

 evil influences of salt water. A few shells (one of 

 which was alive) of Helix anmihis — a species discovered 

 during the Chevert Expedition near the mouth of 

 Katow River, New Guinea — were found, about forty 

 miles south from Katow, at Dungeness Island, Torres' 

 Straits, to which place they are likely to have been 

 carried, Mr. Brazier thinks, on the '-'drift- timber and 

 palm roots which are to be seen floating in the Straits 

 after the north-west monsoons : " the species lives, in the 

 original locality, " in clusters inside of old cocoa-husks,"- 

 and these also, it would seem probable, may have 

 served as vehicles for its transportal. Mr. Liardet has 

 remarked that the numerous small terrestrial shells 



' L. Jenyns (now Blomefield), " Observations in Natural His- 

 tory," p. 321, as quoted in the " Zoologist," (3), x. (1886), 452-3. 

 2 J. Brazier, " Proc. Lin. Soc, N.S.W.," i. (1877), 100. 



