138 HELICIDjE. 



makes it often appear smooth, except near the 

 sutures and umbilicus. 



Mr. Jeffreys, after examining many hundred spe- 

 cimens from different localities, is inclined to think 

 that it must be referred to H. hispida. (Linn. Trans. 

 xiii. 510.) 



Mr. Alder observes that this may be a variety of 

 H. hispida, as was supposed by Mr. Jeffreys, but is 

 stronger, and with the hairs more deciduous, than 

 the usual form of that species. It is very generally 

 diffused, commonly taking the place of Helix glabella 

 (H. rufescens) in situations where the latter is not 

 found. ( Alder, Mag. Z. and B. ii. 107.) 



Mr. Alder also refers to H. circinata of Ferussac, 

 which Rossmasler regards as a distinct species. 



I do not think the four last species are satis- 

 factorily determined; they may be only varieties 

 of one another, or there may be more species ; but 

 this can only be determined by collecting together a 

 very large number of specimens from their natural 

 situations (not as collected among the rejectamenta 

 of rivers), observing how the specimens of the same 

 locality or brood vary, and how the periostraca and 

 the hairiness is affected by their being kept alive, and 

 also by the kind of place they may inhabit. The 

 synonyma of the foreign authors are even more doubt- 

 ful; but this is occasioned by our seldom receiving 

 the same species or variety of these hairy Hydro- 

 manes under the same name, from our foreign cor- 

 respondents and the dealers. Indeed the foreign 

 species, judging from the very different synonyma of 

 the continental authors, are as confused as our own. 





