MONOGRAPH OF BRITISH LAND AND FRESHWATER MOLLUSCA, 103 
GENUS AGRIOLIMAX March. 
The genus A griolimax or field slugs (A ger, 
a field; and Limux) was established in 
1865 by Dr. O. A. L. Moreh, of Copen- 
hagen, the eminent Danish malacologist, 
with whom it is a pleasure to associate 
the genus. 
The acute discernment manifested by 
Dr. Morch in the institution of this genus 
has been fully justified by the structural 
peculiarities which further study has de- 
monstrated to exist. 
Generic Characteristics. — The 
Agriolimaces in their typical species have 
been shown to be quite sharply defined 
internally and externally from the true 
Limaces. Not only is the whole scheme of 
coloration essentially dissimilar in so far 
as there is a total absence of the longi- 
tudinal banding which constitutes so 
striking a feature in Limazr, but the 
arrangement of the gut and the liver or 
digestive gland is on quite a different 
plan, as there are but three typical coils 
“ or tracts of the intestinal canal, as in the 
AL Helicidw, all of which are imbedded 
within the substance of the right lobe of 
the liver, which in this group forms the posterior end of the viscera, 
whereas the left lobe occupies that position in Limaer; the left lobe in 
Agriolimax is laid obliquely in front of the crop, and is not directed back- 
wards, as in the true Limaces. 
Contrary also to what obtains in Limax, where the ingestive or stomach 
tract is the longest, in Agriolima it is the shortest of the series ; further- 
more, the male organ is free in the present genus, and not looped between 
the retractors of the upper and lower tentacles, as in Limae; the whole 
urangement being thus strikingly different in the two groups. 
In addition the viscera have also retained a vestige of the previous 
possession by the animal of a dextrally-coiled external shell, in the strong 
spiral twist to which the internal organs are subjected, a feature which has 
become completely lost in Limaa, as no evidence of a past torsion of the 
viscera 1s now perceptible. 
Geographical Distribution.—'The genus Agriolimax has originated 
within, and is naturally characteristic of the northern hemisphere, its most 
highly organized species belonging to the western palearctic region and 
although it is also found in other and very widely distant places, these 
occurrences are probably solely due to artificial transportation. 
As we have seen in preceding groups, the more primitive or ancestral 
species still existent at the present day have, by stress of competition with 
the more advanced forms, been expelled from the more vigorous districts, 
and are now met with chiefly in the Mediterranean, Caucasian, and other 
regions still more remote from their probable evolutionary area. 
