SCIENCE-GOSSIP. 



227 



colours may be protectively pseudo-sematic, i.e., 

 imitating some other (non-existent) distasteful 

 animal, or perhaps following out the general rule 

 that sematic colours are bright. There is yet a 

 fourth possibility that the colours are, at present, 

 at any rate, of no particular use. That is to say — 

 and I hope the idea, with which I am inclined to 

 agree, is not very rank heresy — Tachea is having 

 what might be described as a " gay time" ; they 

 reproduce so numerously, and apparently suffer 

 from the attacks of so few enemies, that they are 

 varying in all sorts of ways. The conditions of 

 their existence are so favourable, that most of 

 the forms which accidentally (I suppose we must 

 say) arise, are found good, and capable of living, 

 thriving, and multiplying in their surroundings. 

 They further possess very considerable powers of 

 naturalization, as is seen in the North American 

 United States. The very opposite of this is found 

 in.. . .1. which is apparently very 



difficult to transplant with success, and inhabits 

 very restricted and circumscribed areas, even 

 where it is not uncommon. I have failed to 

 introduce it from near Oxford into Herefordshire, 

 and Mr. E. W. Swanton has also failed to 

 naturalize it in Somerset (in some parts of which 

 it occurs). Other experiments seem to have been 

 more successful however ( s ) . 



Considerable plasticity associated with some 

 permanence in the resultant forms is a pyiori rather 

 improbable in species which are keenly engaged in 

 the struggle for existence, especially where great 

 abundance of individuals is superadded. 



There remain one or two more things to be 

 mentioned. From a suggestion of L. E. Adams ( a ) 

 it seems possible that the rather bright, conspic- 

 colouring of Fruticicold cantiana may be 

 sematic, as, according to that authority, it is never 

 eaten by birds. 



\V M Webb ( 10 ) has recorded some interesting 

 observations on Clausilia. He shows that this 

 genua is cryptically shaped and coloured, with 

 reference to such botanical remains as shrivelled 

 •>calcs, etc. I cannot think this a very good 

 case, a.% our CUusttia arc not very geophilous 

 (except C rtjlfhii), and do not, as a rule, occur 

 in the situations indicated. If it is a complete 

 and genuine case, and I am not denying that 

 in many instances it do< e would 



expect to find Clauuli 1 habitually living in silua- 



ild be among ih>: ob 

 which i! Nelson finds 



that C. rolf I among di 



■ 



n II W. 



- 



Uj0U " 1 





J. R. Masefield finds Fruticicola fusca in Stafford- 

 shire on the root leaves of Lychnis dioica, and points 

 out " the striking resemblance which it bears to the 

 dead seed-capsules of that plant, especially when 

 they are wet and transparent with dew or rain " f 1 ' 2 ). 

 J. F. Whiteaves, who found Chilotrema lapicida on 

 brambles, remarks that "it is rather difficult to 

 find, as its shell very much resembles in colour 

 the dark purple hue of the bramble " ( ls ). 



Among the different classes distinguished by 

 their mode of coloration we may note a signi- 

 ficant difference in hibernation. When it was 

 mentioned earlier in this article that Xerophila was 

 resistant to cold, comparison was intended rather 

 with Cryptomphalus and Tachea, than with the 

 smaller, horn-coloured genera. The brightly- 

 coloured species are typical of a warmer climate 

 than England, and in consequence they hibernate 

 in comparatively mild weather. Cryptomphalus, 

 for example, hibernate for a long time, no doubt 

 finding an ordinary English winter rather too 

 severe for its tastes. From September to April, 

 as far as my experience goes, is not an unusual 

 period for it to stay in retirement ( 14 ). That 

 Cryptomphalus does not resist cold well is shown by 

 the large numbers of dead specimens which occur 

 after a winter of some severity. I have noticed in 

 Hereford that it is fond of hibernating at the base 

 of various close-growing garden plants, especially 

 a sort of flag-grass, and after the severe winter of 

 1S94-5 hardly a live specimen was to be found in 

 these situations ( 15 ). I have also found large num- 

 bers of empty shells congregated together in holes 

 in walls, with every appearance (epiphragm, etc.) of 

 having died during hibernation ("'■). Tachea has a 

 similar, though not so extended, range of hiberna- 

 tion. November to March might nearly represent 

 the normal period ("), but they do not, as a rule, 

 occur in abundance between September and April. 

 1 in the other hand, the smaller species, such 

 as Hyalinia, are much more hardy. They are 

 characteristic of a temperate climate, and appear to 

 be only driven in, and that for a short time, by 

 very severe frosts. Viirina pellucida, an essentially 

 boreal species, seems to revel in cold weather ; in 

 the summer it aestivates very deeply and firmly, 

 and it is often difficult to find a live specimen 



[>») 1 1 Man op, cti„ p. H2. 



lit of O ford '"I' Mollui 1 .1 ' 1 '. p. .'<. This 

 1 , 1. m.ni ably good Etnd Interesting local Fauna. 



ly 17th, In " Z01 i' ii' ' 1) 1 " ' M p. |»4. Iiiiin.i 



1 Infrequentl) 1 1 1 /infl, fairly 



11 rii.- middle -■( ■■'. i'"' 1 e,g„ Dei eml th 



enfoi in!" 1 n- I-. 1 in 1 1 often 



do ii"' •-■.in -.I ill' afi it. 1 ' fu 1 '■■ '" I'll. 1 ii iln 



»hen Ihi ' 'I'll- nil i" find, which 



I deal ol ! iroti 1 tlon Crypi • oini "mi"' 



linn' '. -. .,1 ii. 1 '.'. 1 ' "ii. [uoted I-.- a. n. 1 ooko, 



"/-. ni.|i in i"i additional ■ ' 1 

 (i'-i < 1 < / 1 ' 1 ,1, v. (1881I, I'. 11 l" ■ prln i"'i 



' "i "' 'i' 1" ' """ ■ 



1 urprlaed to find a alngli 



»i ri> , i 1 , j iM .1 11. 1, ford, 



■ on ' i" 'i'" i"'"i Ov ii'" 1 "i'i ■ prlng, 



,i "iin'i bi n lApi 'i iota). 



