100 
TH. MORTENSEN, 
(Schwed. Südpolar-Exp. 
Zoogeographica! remarks. 
In the »Echinoiden der deutschen Stidpolar-Expedition» (p. 92 — 105) a general 
account of the Zoogeography of the antarctic-subantarctic Echinoid-fauna is given, 
the main results being the following: The South American (Patagonian-Chilian) 
littoral region must be regarded as the centre of the whole antarctic-subantarctic 
region; a very great proportion of the Echinoids occurring in the Patagonian region 
are known from this region alone, while others are known also from the Antarctic 
region ( Arbacia Dufresnii , Sterechinus Neumayeri , Abatus cavernosus (?) and Austro- 
cidaris canaliculata (?)). This bears testimony of a former connection between South 
America and the Antarctic Continent; especially the occurrence of the viviparous 
genus Abatus in both these regions is conclusive evidence of such a connection, even 
if it be ultimately proved that the species cavernosus does not really occur at the 
antarctic coast. P'urther the Echinoids prove that the Kerguelen-group also belongs 
to the Patagonian region; the occurrence there of Abatus cordatus , very nearly related 
to the Patagonian species Abatus cavernosus and A. Agassizii, and of Eurocidaris nutrix , 
nearly related to the Patagonian Austrocidaris canaliculata points to the existence of 
a former land or shallow water connection between Kerguelen and South America; 
especially the Abatus species, being viviparous and a littoral species, cannot possibly 
have come to Kerguelen over the vast deep sea now separating this group of islands 
from South America. Also a transportation on algae, 1 which might be possible for 
Eurocidaris , is excluded for this species. 
To the Echinoid fauna of South Africa and New Zealand the Patagonian fauna 
has no relation whatever, 2 a fact in direct contradiction to the hypothesis of a former 
land connection between these regions, directly or indirectly (over the antarctic con- 
1 I may recall the observation of Protocentrotus angulosus carried on floating algæ in the Atlantic 
recorded in the »Echinoiden d. deutschen Siidpolar-Exped.» p. 61. 
2 The occurrence of a species of the genus Notechinus at New Zealand (Stewart Island) (cf. p. 40, 
Note) cannot give evidence for the supposed land connection with South America. The genus Notechinus 
is widely distributed in the subantarctic region, and has most probably pelagic larvæ, which may be trans- 
ported by the currents. — I may here also recall the fact that the quite recent indication by Rudmose 
Brown of the occurrence of » Goniocidaris » canaliculata at South Africa has proved to be erroneous, being 
due to a wrong determination (cf. p. 19. Note). 
