8 Experiments on the Development of the Liver-fliihe. 
known there, and these have been identified as A. atcr and 
Limax cinercus. The last-mentioned slug does not occur in 
the Faroe Islands, but the other four species are common to the 
two places, and one of them must be capable of acting as inter- 
mediate host to Fasciola. The question of distribution is further 
discussed in the following paper, for which I am indebted to 
Professor RoUeston. It appeared in the ' Zoologischer Anzeiger ' 
of Aug. 9, 1880. 
Note on the Geographical Distribution of Limax agrestis, Arion hor- 
tensis, and Fasciola hepatica. By George Eolleston, F.E.S., 
Linacre Professor of Anatomy and Physiology, Oxford. 
That some not inconsiderable confusion exists as to the 
question of the existence of Arion ater and Limax agrestis in 
Greenland, will be seen from the following quotation, to be 
found as hereinafter specified : — 
'A Manual of the Natural History, Geology, and Physics 
of Greenland, together with Instructions for the Use of 
the Arctic Expedition.' 1875. London. 
{P. 124.) " Mollusca Groenlandica : 
Classis i. ANDROGYNA, Morch. 
Ordo i. Geophila, Fer. 
*1. Arion fuscus, Mlill. Probably intro- 
duced. L. agrestis, L., according to 
VVormskiold. 
The species marked with an * are doubtful inhabitants of Greenland." 
Prefixed to the list whence the above passage is taken is a note 
to the effect that the list is the " Prodromus Faunae Molluscorum 
Groenlandiae (in Rink's ' Gronland,' »Scc., 1857, pp. 75-100). 
By Dr. O. A. L. Morch. Revised and augmented by Dr. O. A. 
L. Morch, University Museum, Copenhagen. April, 1875." 
On referring, however, to the Prodromus itself, as published 
in Danish in 1857, I find the entry which concerns us stands 
simply thus : — 
" Mollusca Gronlandica : 
Order i. GeOPHILA. 
Gen. i. Limax, L. 
*1. L. agrestis, L. (ifolge Wormskjold). 
*retigner at Artens Forekomst paa Gronland ikke er sikker." 
That is to say, that the line in the entry given in the Manual 
of 1875 — " * Arion fuscus, Miill. Probably introduced " — is alto- 
gether something fresh and new ; whilst the asterisk, denoting 
that the animal so marked is possibly not indigenous, was 
