BARDWICKE'S SCIENCE-GOSSIP. 



265 



SLUG GOSSIP. 



By Dr. J. W. WILLIAMS, M.A., Editor of the 'Naturalists 1 Monthly: 



[Continued from j>age 244. 1 



Fam. 3.— Helicid^:.— Subfam. Arionina. 



EN. Avion, Ferus- 

 sac. 1819. — Arion 

 atcr, Linn. 1758. 



Baudon, in J. de 

 Conch., vol. xxxii. 

 p. 320, describes a 

 specimen with the 

 respiratory orifice 

 on the left side, 

 i.e. sinistral. A 

 like condition has 

 been described by 

 Seibert, in Limax 

 Schwabii, Frauenf. 

 (Mai. Bl. xxi. p. 

 198). Leydig 

 (Arch. f. Nat. vol. 

 xliii. pp. 265-273) 

 says that the dark 

 coloured varieties 

 are mostly found 

 by him in damp localities, and the red ones in dry 

 places. The same writer also says, that what has 

 been described as Arion tenellns is in reality the young 

 of A. ater. This last is one of the many instances in 

 which young specimens of well-known slugs have 

 been described as new species, another instance of 

 which I gave in a note to the February number of 

 this paper. Mayhap it will be interesting to many 

 to know, that the fact of A. ater feeding on dead 

 earth-worms — which has been often noted in the 

 pages of this journal — was first mentioned by Power, 

 on p. 323 of the ninth volume of the Transactions of 

 the Linuean Society. 



Krukenberg has been analysing how much water 

 this slug has in its body, and finds it 86 per cent. 

 (Vergl. Phys. Studien, ii. pp. 103, 104.) 



H. Simroth, in Nachr. Mai. Ges. 1SS4, pp. 59-61, 

 says that Arion ater grows to its full manhood in 

 about a year. The old adage: "There's nothing 

 new under the sun." This fact had been noticed 

 years ago by many who gave their attention to the 

 No. 276. — December 1887. 



slugs in the primitive times of the work. I know 

 Bouchard mentions it. 



Arion atcr lays its eggs between the months of 

 May and September, from seventy to a hundred in 

 number ; the young are hatched in from twenty-six 

 to forty days, and they begin to oviposl a month or 

 two before they attain adulthood. 



Nunneley remarks, in the first volume of the Leeds 

 Transactions, that this slug lives much longer than the 

 Limaces. 



Arion albus. — I wonder if we have such a British 

 slug. Mr. Alder was the first to record it so in his 

 " Catalogue of the Molluscs of Northumberland " 

 (p. 30). In it he says : " Our individual was about 

 an inch in length, with the body whitish, having a 

 faint greyish tinge above. The shield and the 

 posterior parts of the body near the tail were of a 

 pale canary colour ; tentacles greyish-white ; the 

 mucus was deep orange yellow." 



A specimen was taken later by Blacklock, in the 

 same district, which was darker in tint, more greenish 

 on the back, and more orange-coloured on the 

 mantle — in this "taking" the tentacles were eyeless, 

 no doubt a deformity. 



Possibly it has died out of our fauna, for Bouchard 

 Chautereaux, in Mem. Soc. Ag. Boul. 2nd ser. 

 vol. i. p. 159, says that it is unprolific. The same 

 author also states that it lays its eggs from Septem- 

 ber to December. 



Arion subfusats, Drp. — This new instalment into 

 our slug list was named by Draparnaud , in 1 805 . Linne 

 in his Swedish fauna, located it under his L. rufus. 

 Nilsson, in 1822, called it A. fasciatus, while Wester- 

 lund, writing in 1871, has L. rufus et snbfuscus. The 

 reader will recognise it by the following descriptive 

 characters : It is of medium size, and cylindrical in 

 outline, with a faint band running along both sides 

 of the body ; the hinder portion of the back is sub- 

 carinated and finely scaled ; the mantle elongated, 

 and the under portion of the sole becomes attenuated 

 by degrees, terminating in a rounded apex ; length 

 40 to 60, width 6 to 10 mm. Then there are a good 



N 



