KEW : ON THE MUCUS-TIIREADS OF LAND-ST.UGS. 157 



aii'oruiii, the spinner par excellence of the books ; but this slug, when 

 experimented upon, spins less readily than those of other genera, e.j;:;., 

 Agriolimax, etc. Mr. Standen informs me that he has seen L. arhoruni 

 suspended under natural conditions — the same observation has been 

 made by Bouchard-Chantereaux (lo) and by Thomson (48). Similarly 

 Lister (i) saw Limax hanging from trees ; Zykoff (41) saw young Avion 

 ater descending voluntarily in a vivarium ; Agriolimax agrestis has 

 been found by Bree (8), Harte (23), Eimer (30), and Crowther (50) 

 descending from trees, and by Binney (20), presumably, from plants 

 and fences ; unidentified, or doubtfully identified slugs, moreover, have 

 been seen hanging from plants, rafters, or the glass in greenhouses by 

 Saunders (19), Warner (34, 35), Woolford (49), as well as by three 

 anonymous writers, and six other observers have seen the creatures 

 spinning voluntarily from trees, projecting parts of buildings, etc. ; 

 Blandford (46) saw slugs descending from sheaves on the wagon or 

 stack at harvest-time, and D.T. (33) saw them coming down in num- 

 bers from clover in a loft over horses. Other than these, most of the 

 observations recorded by authors, and all those of the writer, have been 

 made by way of experiment. 



It is easy to induce the creatures to make threads, for they will often 

 do so if placed on small objects or in uncongenial places of any kind. 

 Mr. Crawshay tells me that he has placed the animals for this purpose 

 on the underside of pieces of glass held horizontally. In my own 

 experiments the slugs were usually placed on twigs of needle-furze 

 held in vases. 



The behaviour of the creatures when placed on the twigs differs con- 

 siderably in individuals of the same species. I have not noticed, 

 however, that the species or genera differ in any marked degree, either 

 in their manner of proceeding or in the perfection or imperfection of 

 their spinning-powers, except that their actions in this respect are 

 influenced by weight. Agriolimax spins a little better and more readily 

 than other slugs ; next, I think, come Amalia and small specimens of 

 Avion; and last Limax. Some individuals remain for a considerable 

 time on the twigs, turning back when they approach the extremities ; 

 some, before abandoning themselves to a thread, stretch out in all 

 directions in search of a fresh support, while others glide off immedi- 

 ately without hesitation. During descent some continually turn about 

 and stretch out the anterior parts in search of a landing-place, and it 

 sometimes happens that the animal revolves slowly ; by other indi- 

 viduals, however, few movements are executed, the animal maintaining 

 its crawling position, and descending steadily as if resigned to its fate. 



The gliding from an object is effected by the creature's ordinary 

 crawling locomotion, the anterior part of the body being extended over 

 the edge of the object, so as to become free. The animal can main- 



