210 Dr. E. von Martens on the Species of Amphipeplea. 
selves are the country of the Achatinelle, in many of which the 
same peculiarity obtains; and it seems at least not absurd to 
assume that the same may occur in the genus Limneus. Let us 
hope that the zeal of the Sandwichian malacologists, which within 
the last few years has enriched science with so many new species, 
will take up and furnish an early answer to this question. 
IV. On the species of Amphipeplea. 
Amphipeplea is distinguished from Limneus by the external 
expansion of the mantle in the living animal ; and this expansion 
can be traced by the existence of a more whitish and less glossy 
deposition on the outside of the shell. Various authors have in- 
troduced into the genus species based only on the involuted 
whorls and thinness of the shell, without regard to the above 
characters. 
1. European Species.—The only one of all the Palearctic 
species which certainly belongs to Amphipeplea is, so far as I 
know, A. glutinosa, Mull. sp., the type of the genus. Ehrenberg 
(Symbol Physice, 1828) distinguished from it, as a subspecies, 
his A. glutinosa syriaca from Beirut, chiefly because he could not 
believe that the same species should inhabit Sweden and Syria. 
I have examined the typical specimen in the Berlin Museum, 
and cannot detect any constant differences between it and speci- 
mens from Sweden and northern Germany. 
The deposit on the outside of the shell occupies in A. glutinosa 
only a circumscribed part of the last whorl near to the columella, 
and is nothing else than a slight enlargement of the parietal 
lamina, which can be distinguished in all specimens of Limneus 
rather from its difference in colour and gloss than as a formally 
distinct superposition. The spire is entirely free from any ex- 
ternal deposit. Nevertheless it is well ascertained by different 
authors (and I have had opportunity of noticing it myself) that 
the external lobes of the mantle can be produced far beyond the 
limits marked on the shell, these indicating only, I suppose, a 
mean average or stationary ‘degree of expansion. 
The eeosraphical distribution of Amphipeplea glutinosa ex- 
tends from the Polar Circle, in the Baltic provinces of Russia, to 
Sweden, Denmark, and the northern half of Germany (where it 
is rather local and rare), Holland, England, the northern and 
western parts of France. Its southern limits are not yet as- 
certained; in southern Germany it has not yet been found, so 
far as I know; and only two stations for it are recorded in 
the whole Mediterranean province—Rome (by Cantraine) and 
Beirut. 
Beck (Index Molluscorum, 1837, p. 115) introduced the 
Limneus ampullaceus, Rossm., into the genus Amphipeplea. This 
