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HARDWICKE'S SCIENCE-GOSSIP. 



was attended by them, and they were accompanied 

 by brilliant white masses of the cloud termed 

 (cumulo-cirrus), and also incipient "festoon" cloud. 

 Respecting the latter cloud, I ought to correct the 

 impression produced by the woodcut in Science- 

 Gossip for September, the effect being much too 

 hard and defined, especially on the upper side. But 

 as the engraving, which does not fairly represent the 

 festoon-cloud, has appeared, I may utilise it by 

 saying that if the curved patches given there were 

 straightened and so seen in a turbid and mixed 

 nimbus sky, they would fairly give an idea of a more 

 rare phenomenon, viz., the cylinder cloud. 



This "cylinder" is a connecting link between 

 cumulus and stratus ; it is seen at any angle with the 

 horizon, and indicates the presence of a vast quantity 

 of vapour in the atmosphere. It appeared many 

 times during the very wet summer of 1879. 



Samuel Barber. 

 {To be continued.) 



SLUG GOSSIP. 



By Dr. J. W. Williams, M.A., Editor of the 



Naturalists' 1 Monthly. 



FOR this communication I want to transcribe 

 from the pages of my note-book such facts and 

 features of the tardy-gaited ones as will most interest 

 the readers of Science-Gossip, and more particu- 

 larly such of them as in any form or manner relate to 

 the working of, and work done by, our continental 

 brethren on the British species, for by so doing I 

 shall bring the reader up on to the verge of the ever- 

 advancing wave of knowledge in this direction. I 

 shall also refer here and there to the archaic work of 

 our ancestors, especially such as are missed or looked 

 over by the writers of our present text-books, inter- 

 polated now and again by remarks of my own. 



And first I want to draw the attention of the 

 curious to what old Swammerdam said about the 

 shell of the slug, or, as it was called in his days, the 

 snail's stone. Accounting for the larger kinds pos- 

 sessing "very small membranous plates, while the 

 smaller ones had them often much larger and formed 

 of solid stone," he says, " that the snails change this, 

 their little stone, yearly in the same manner as craw- 

 fish change those two semi-convex and plain stones 

 which are likewise placed in their thorax and are 

 properly called crabs' eyes." Swammerdam was a 

 queer fish ! The fact never struck him that these 

 shells varied in the various species and genera. But 

 he did a good deal in his time, and I am sure ento- 

 mological friends will honour his memory, for it was 

 he who first discovered metamorphosis, and in 16S5 

 he dissected a butterfly from its aurelia before the 

 Grand Duke of Tuscany. 



Speaking of the shells of slugs reminds me that 

 Mr. Grant Allen states in one of his interesting papers 



— I forget in which of his books this is, but the reader 

 will instantly call the article to his memory — that the 

 limaces are higher in the scale of existence than the 

 arions on account of the greater development of their 

 shell, and the testacella; above the limaces for the 

 same reason. I would call his notice, and that of all 

 readers of the article in question, to the conflicting 

 statement of Mr. Godwin Austen, in his " Land and 

 Fresh-water Mollusca of India" (vol. iv. p. 157), 

 wherein he states that in his opinion those genera 

 with a rudimentary shell and mantle lobes in strong 

 development are higher in the scale of existence than 

 those with a shell more greatly developed. But to 

 proceed : — 



Fam. 1. — Testacellid^. 



Gen. Testacella. — This genus was created by Cuvier 

 in one of the tables accompanying the first volume of 

 his " Anatomie Comparee," which was printed in 

 1800. Draparnaud and Lamarck adopted the name 

 at nearly the same time (1S01). Specimens had been 

 found, however, in France, for a long time previous 

 to the Baron's publishing his tome, by Dugue of 

 Dieppe, in 1740; by Guillemeen, in Niort and 

 Rochelle in 1754; and also by Querhoent, of Croisic, 

 in 1779. From these workers specimens were sent 

 to Cuvier, Draparnaud, and Lamarck. On the other 

 hand, there are those who say that it was Faure 

 Biguet who first discovered the snail slug and called 

 it Testacellus — a name, they say, afterwards changed 

 by Draparnaud and Cuvier to Testacella. 



T. Mategei, Fer. — Lamarck described this slug in 

 1S01 as T. haliotides. Miller, in the " Annals of 

 Philosophy," was the first to describe it as British, 

 and I dare say every reader knows it was first intro- 

 duced into our fauna by Mauge, who brought it over 

 with some plants for the Bristol Botanical Gardens, 

 from Teneriffe, where it in process of time became 

 acclimated, and it still remains with us. 



T. haliotidea, Drp. — A Mrs. Smith was the first 

 to describe this slug as a native of our island, who 

 found some shells and afterwards some creatures of 

 the scutulum variety in her garden at Bristol. 



During the months of May, June and July, 

 Haliotidea lays its eggs — from ten to fifteen in 

 number only — in a subterranean gallery, and not as 

 in other slugs massed together, but separated from 

 each other, from which exclude the young ones in a 

 period averaging from twenty-five to thirty days. 

 They are carnivorous in eating, and not only car- 

 nivorous but they are also cannibals. Mr. Lowe, in 

 the 53rd meeting Reports of the British Association, 

 1S83, p. 549, mentions a good case in point of this : 

 — In twenty-four hours 25 specimens put out of sight 

 twenty-five earth-worms and the same number of 

 L. agrestis. Cabbage growers, if they knew this, 

 would wish, I opine, that there were more of these 

 slug-eating slugs about, but unfortunately their repro- 

 ductive powers are very meagre. When found in 



