JOURNAL OF CONCHOLOGY, VOL. ID, NO. 4, OCTOBER, I90I. 



lives on trees, from which they can thus malce a convenient descent to the earth. . . . 

 It may serve also as a means by which they can suddenly escape from the attacks of 

 their enemies, and particularly of birds. . . . They often remain suspended in 

 mid-air for a time, and it is not unlikely that there is some pleasurable sensation 

 connected with the act, which induces them thus to prolong it. We have seen the 

 descent actually practised by every one of our Atlantic species. 



Binney gives, without description, a wood-cut of a slug descending 

 from a twig (fig. 4). The information is repeated by W. G. Binney 

 (Terrestrial air-breathing Mollusks, vol. 5, 1878), and the figure is 

 said to represent yigr. campestris; after the statement "we have seen 

 the descent actually practised by every 

 one of our Atlantic species," is added 

 "as well as by the large Pacific Ario- 

 Itjuax;" but this is a mistake, for Mr. 

 W. G. Binney tells me that he has not 

 seen ArioUmax suspended. Dr. Cooper 

 has stated that Arioiimax columbianus, 

 in dense damp forests near the Pacific, 

 "not unfrequently drops from the trees ;"^ 

 but this, as Dr. Cooper informs me, does 

 not mean that the creature lowers itself 

 by a thread. 



21. Forbes & Hanley. History of 

 British Mollusca,voL 4, 1853, p. 287. 



'■'■Arionflavus" — probably Arion miiit- 

 vius — suspends itself. 



22. Reeve, L. Land and Freshwater 

 Mollusks indigenous to or naturalized 

 in the British Isles, 1863, p. 26. 



Liinax maxhnus — size not indicated — escaped from a glass on a 

 mantel and let itself down into the fender, a distance of 3-4 feet, in 

 about five minutes. 



23. Harte, W. Note on certain movements of the Limacidpe, Proc. 

 Nat. Hist. Soc. Dublin, vol. 4, 1865, p. 182: 



Some time since my attention was caught by a slug descending from the branch 

 of a tree in my garden, and which had lowered itself by a thread some three or four 

 feet. ... I observed one fact which I believe is new, viz., that they possess 

 the power of re-ascending by means of the same thread ; and I am inclined to think 

 that this accounts for the fact of their being so seldom seen descending. The leaving 

 the branch in the first instance I believe to be altogether an involuntary act. 

 A slug descends lay creeping along a drooping branch, when it comes to the extreme 

 jjoint of which it may be seen projecting over the end, seeking for fresh footing, its 

 body mean\\ hile slipping down by gravitation ; and at last, having lost its hold, it 

 is supported only by means of a thread. ... It continues to descend by 

 gravitation alone; and if the condition of the animal, or the atmosphere, is not 



I Cooper, " Nat. Hist, of Washington Territory," 1859, p. 377, 



Fig. 4. 



After Binney, Terrestrial Air- 

 Breathing Mollusks of the United 

 States, vol. I, 1 85 1, p. 175. 



