73 
ceptional accidents and whose occurence in Bornholm therefore 
supports the assumption that this island has been connected with 
the continent during the late-quaternary period. Such animals are 
Erinaceus europæus (which, however, was possibly imported by 
man), the reptiles, the amphibians, the land-molluscs, many insects 
(butterflies, etc.) and other Invertebrates. 
The theory that Bornholm has been connected with North Ger- 
many is supported by many positive geological facts. If, however, 
the island of Gottand has never been more or less closely con¬ 
nected with the continent since the ice-age, it must be admitted 
that the animals in question may have immigrated to Bornholm 
just as well after the disappearance of the land-bridge as before, 
and no conclusions with regard to the time of immigration can be 
drawn. Munthe has pointed out that there are evidences of a 
considerable upheaval of land in the Southern Baltic area in early 
post-glacial time and supposes that a land-connection was establ- 
ished between North Germany and Gottland—Oland (an upheaval 
of about 60 m E. of Bornholm would be sufficient, cf. the map 
fig. 2); this hypothesis, though not proved, is strengthened by the 
occurence of the above-mentioned animals and can for the present 
be maintained as a working hypothesis. 
The fauna of Bornholm contains, inter alia, many species with 
a more or less southerly distribution, the northern boundary pas- 
sing through Denmark or Southern Sweden. If these animals have 
immigrated over the land-connection, this was still in existence at 
a time when the climate was as warm as it is to-day. Several of 
these species occur in the Southern Baltic district only at isolated 
localities, outside the area of continuous distribution, and are pre- 
sumably, in Bornholm and in the other Scandinavian localities, 
relics from a warmer period. Such animals are Hana agilis , the 
land-shells Pupa avenacea, P. cylindracea and Clausilia plicata , 
several insects (the butterflies Coscinia striata , Agrotis glareosa , 
A. janthina , A. cinerea, Selidosema ericetaria and others). To 
judge from the occurrence of these species, the land-connection 
between Bornholm and the continent existed during the first part 
of the post-glacial period of warmth. Probably Enig s orbicularis 
and Sus scrofa ferus , which are now extinct over the whole of 
Scandinavia, also immigrated during this time. 
