9 8 



HA RD WICKE'S SCIENCE-G OSSIP. 



nances when in repose wear a very similar expression. 

 No doubt we often say of a certain creature that he 

 is very cunning-looking, lazy-looking, etc., but this 

 sort of expression will be found to be very limited. 

 In any case, this particular form of animal beauty is 

 occasioned by a perpetual tincture of mental force 

 permeating as it were the stream of electric or vital 

 energy flowing from within towards the countenance 

 and the other more impressionable parts of the 

 frame ; and in man it will be found that it is those 

 mental states that are most characteristically human, 

 elated rather than depressed, and lively within certain 

 limits, whose external manifestations can strictly be 

 denominated beautiful. 



THE VARIATION AND ABNORMAL 

 DEVELOPMENT OF THE MOLLUSCA. 



Part III. 

 Terrestrial Gasteropoda (continued). 



[Continued from p. 226.] 



T TEL1XPOMA TIA.— From the neighbourhood 

 J. JL of Caterham I have some spirally grooved 

 specimens, such as may be seen in the British Museum, 

 and also an unusually conical one. Mr. J. W. Wil- 

 liams has found a specimen near Dorking which is 

 probably identical with Jeffreys' variety albida. The 

 specimen, which was alive, was of a very pale- 

 yellowish or straw-colour, except where the epidermis 

 had been destroyed, where it was pure white, the 

 colour being due to the epidermis only. The lip of 

 the shell was white. Many varieties of this species 

 have been found abroad ; the following are not un- 

 likely to turn up in England : — 



Var. quinqnefasciata, Moq. — Yellowish, with five 

 continuous bands ; var. brnnnea, Moq., brown, with 

 the bands scarcely visible ; var. unicolor, Westerlund, 

 unicolorous, bandless ; var. parva, Moq., very small ; 

 monst. sinistrorsum, Born, spire sinistral ; and 

 monst. scalare, Chem. (scalariforme) whorls partly 

 disunited. 



Helix aspersa. — I have found the variety zonata 

 near Otford, and at Chislehurst a small variety, a 

 variety approaching undulata, and a dark form allied 

 to var. nigrescens. A conical variety also occurs at 

 Chislehurst (L. M. C), and a monstrosity deeply 

 grooved at the suture (S. C. C). 



There is also a variety, which might be called 

 semi-fusca, having the band-fornnula (123)45, all the 

 space between the suture and the situation at the 

 lower edge of the third band being chocolate-brown. 



Var. exalbida. — I have found this variety plentiful 

 but local at Dartford, and at Warlingham. Chisle- 

 hurst (L. M. C. and S. C. C), Dorking (Ashford). 

 Both at Warlingham and at Dartford the specimens 

 were amongst Clematis vitalba, and at first sight it 

 might seem that the white colour of the shells served 

 to protect them on account of their resemblance to the 



white Clematis flowers, and had been assumed for this 

 reason ; but against this view there are three facts : 



(1) That a number of broken exalbida shells 

 were found under the Clematis bushes at Warlingham ; 



(2) that the type form was also present ; (3) and 

 that my brothers found var. exalbida on Pteris in a 

 locality some little distance from any Clematis. 



I cannot help thinking that it would save a lot of 

 trouble if all white or albino forms were called 

 simply var. alba, instead of one being exalbida, 

 another albida, another albinos, or albina, and so on ; 

 and in the same way other sets of varieties, so to 

 speak, might be named. The following occur to me 

 at the moment — var. major, shell one-third larger 

 than type, and var. minor, one-third smaller, var. or 

 monst. scalariforme, whorls separated, or suture near 

 mouth of shell, forming a specified angle, var. 

 fasciata, having one or more bands abnormally 

 developed, as mentioned above, in connection with 

 Limna:a. In this connection I may mention three 

 interesting cases of abnormal banding, in which 

 there was banding (when I say banding in these 

 cases, I mean whitish and generally linear bands, 

 possibly due to disease) above the periphery as well 

 as below. The first is in a specimen of L. peregra 

 var. Burnetti, from Loch Skene, in Mr. Ponsonby's 

 collection; the second is an example of L. glutiiiosa, 

 from Reading, collected by Mr. W. Holland, in my 

 brother's collection, which, should these bands be 

 homologous with the normal banding of Helices, 

 would have a formula 12(345), anc ^ tne third is 

 Limncea Langsdorffi, of which there are specimens in 

 the British Museum. 



With regard to albino varieties (which, it must be 

 remembered, are merely varieties of the shell— the 

 animal is normal), it would be interesting to learn 

 whether they are equally abundant in ail countries, 

 or whether some districts are free from them, and 

 whether there are any large classes of mollusca in 

 which they never occur. 



According to J. B. Dietz, the albino variety of 

 Helix hortensis is more common in wet years, and 

 specimens with coloured bands have the growth of 

 the last wet year not coloured. But I certainly think 

 this needs confirmation. 



It is extremely interesting to note how a character, 

 which arose as a pathological phenomenon, may, by 

 transmission, become the character of a species, of a 

 genus, of a class, and how what is pathological and 

 abnormal in one form is normal in another ; thus, in 

 the genus Hyalina : 



(1.) cellar ia has the albino form very rare, and 



quite abnormal ; 

 (2.) piira has it as common as the type ; and 

 (3.) crystallina is always albino. 



Again, in Litnntea, Bythinia, etc., decollation is 

 clearly abnormal ; but in Bulimus decollatus and 

 some other species, it is strictly normal. 



T. D. A. COCKERELL. 



