ATLANTIC SPECIES 19 
Norway has the following which have not been found 
in France : 
Gymnomitrium crenulatum. Leptocyphus cuneifolius. 
Marsupella Boeckii. Herberta adunca. 
Anastrophyllum Donianum. Scapania ornithopodioides. 
Sphenolobus Pearson. Radula aquilegia. 
Plagiochila tridenticulata (as R. Carringtonii. 
P. exigua). Pleurozia purpurea. 
The following have been found in France but not in 
Norway : e 
Dumortiera irrigua. Drepanolejeunea — hamati-' 
Lophocolea spicata. folia. 
Colurolejeunea calyptrifolia. Marchesinia Mackaii. 
Cololejeunea minutissima. Jubula Hutchinsie. 
The Atlantic species are the most interesting of our 
Hepatice. They differ from our other groups, Northern, 
Continental, and Mediterranean, in that their origin in our 
country cannot be traced to any known geological period. 
The peculiar British species, and some of the others, are sub- 
tropical or tropical. They are the relics of an early warmer 
period. Comparatively few have been found in fruit, and 
as gemme are also unknown in some of them, they are in 
many cases no doubt in process of extinction. Further 
investigation will doubtless alter our views on some of 
these species, and it is with some hesitation that I have 
included the generally accepted Atlantic species Gymno- 
mitrium crenulatum and Herberta adunca, as they have 
been recorded from Alaska. Perhaps all alpine Atlantic 
species may be found to be in a different category from the 
species peculiar to sheltered places on the low ground, but 
here as with other groups there are always a few species 
which are difficult to classify. 
WESTERN SPECIES OTHER THAN ATLANTIC 
Most of the low-ground species are found in greater abund- 
ance on the west side of the country than on the east, but 
the following show a distinct preference for the west side: 
