336 Rev. B.J. Clarke on Irish species of the genus Limax. 



max. It agrees with Limax cinereus in having the hinder ex- 

 tremity of the mantle produced^ but in almost every other respect 

 it will be found to differ materially. First, it is much smaller 

 in size, never attaining that of full-grown specimens of L. max- 

 imus. Secondly, in colour it likewise differs, possessing the pecu- 

 liar smooth blue glaucous colour and gelatine translucency which 

 in all its stages and varieties serve to point it out. By the 

 markings on the mantle it is also easily distinguishable from L. 

 maximus, as the two fasciae are almost always more or less appa- 

 rent, and which I have never seen in any of the varieties of L. 

 maximus. Thirdly, the keel is much shorter, and does not exhibit 

 that crenated edge which is so conspicuous in L. maximus. 



To Limax flavus it more nearly approaches in size and general 

 contour, but is somewhat smaller and of a more slender form ; it 

 may be however at once distinguished by the form of the termi- 

 nation of the mantle, which, instead of being rounded, as in L. 

 flavus, is produced and tapers off to a blunt point : this feature 

 is more apparent when the animal crawls than when it is at rest. 

 In colour and markings it is so widely distinct that I need hardly 

 notice them ; the presence of fascise and its own peculiar glaucous 

 tint will generally serve to distinguish it ; and however nearly it 

 may approach to any of the varieties of Limax maximus or L. fla- 

 vus in the markings of the body, there will always remain, even in 

 the palest specimens, sufficient traces of the fascise on the mantle 

 to mark the species. 



The mucus of L. arboreus is colourless, whereas that of L. fla- 

 vus is yellow when thrown into hot water. 



M. Bouchard^s description of the habits of this Limax — should 

 it prove to be identical with his — agrees in a great measure with 

 my own observations. He observes : — " They live on trees, but 

 prefer those which are old, covered with moss, and of which part 

 of the wood is rotten ; when the weather is cloudy or rainy^ they 

 are seen crawling upon the trunks or branches.^' When seen in 

 this position against the light, they present a very interesting and 

 curious appearance on account of their great translucency, which 

 permits their internal organization to be indistinctly traced. 

 " The mucus of this slug is colom'less and very abundant ; the 

 animal possesses the remarkable property of emitting a clear cold 

 liquid like the purest water when touched." I find this is only 

 to be observed when the animal is first taken in the hand from 

 off the tree, and loses the power of repeating it when kept in con- 

 finement. I have attentively watched this phsenomenon, and 

 have observed that the hquid is given off from the hinder part 

 of the shield. " They feed themselves with the detritus of the 

 decayed wood and do not touch the leaves, at least of those trees 

 which I have carefully examined, and never found a leaf either 



