ScHARFF — On the Slugs of Ireland. 555 



in their youth, and the colour of the adults varies between black, brown, and red 

 in Germany, just as it does in Ireland, with the exception that the brick-red form 

 so common in Grermany is absent with us. 



Simroth's experiment of offering A. ater as food to various birds, and its being 

 refused by them, does not seem to me conclusive, as birds kept in captivity get a 

 regular diet, and become in time rather dainty feeders. Besides, large birds such 

 as gulls, are decidedly rare in Germany, and I think it much more likely that 

 toads or some of the insectivorous mammals do a great deal of damage among 

 slugs ; and it is possibly these that have a particular aversion to the bright red 

 slugs, owing to their more acrid slime. Their colour is certainly most conspicuous, 

 and on a rainy day they are often seen in hundreds in broad daylight in the 

 forests of Germany. 



I do not believe their colour is influenced by the temperature, for we find black 

 and brown forms of the same species living in such a dry climate as that of Eastern 

 Germany and on the very humid West Coast of Ireland — in cold and bleak Norway 

 as well as on the parched plains of Spain and Portugal. 



In this country, as I mentioned before, I have met with the uniformly black, 

 the brown, olive, claret, and light red varieties of A. ater, and one variety which 

 is black above, with yellow sides. The olive and light red forms occur only on the 

 West Coast, but the black and brown ones are equally common there. In boggy 

 ground most of those I saw were either olive or a rich burnt sienna brown. Their 

 colour harmonizes most perfectly with the brown of the turf and the oKve-coloured 

 moss growing on it. I have also observed the light red in that neighbourhood, but 

 no natural object seemed to me to exactly resemble it. 



Perhaps the wettest spot on the West Coast is the Skellig Rock, an immense 

 rock, entirely bare, over the greater part of which the huge Atlantic waves break, 

 scattering their spray completely over the highest parts. From this rock I have 

 the olive and black variety of A. ater. If moisture caused darkness, they would 

 all be black there, for a more humid place can scarcely be imagined. 



Certainly, I have everywhere met with black specimens very close to the sea, 

 both on the West and especially on the East Coast, and that fact taken alone might 

 lead us to suppose that moisture had something to do with the darkness of their 

 colour ; but black specimens are equally common inland a long way from the sea, 

 whilst on cultivated ground, even if it should be quite close to the shore, we find 

 almost invariably the brown variety. 



Another remarkable circumstance is that along the sea-shore near Dublin one 

 meets very frequently with the black and yellow variety, i.e. black with yellow sides 

 (Plate LVI., fig. 15.) A variety with white sides has been recorded from the coast 

 of Wales, and Simroth obtained them also from the shores of the German Ocean. 



