138 
HELICID^. 
makes it often appear smooth, except near the 
sutures and umbilicus. 
Mr. J effreys, 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 F erussac, 
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. 
