220 NILS HJ. ODHNER 
otherwise not in the Peruvian Province); to the northern, for instance, Lama 
angulata (Gulf of Panama to J. Fernandez). 
Except for the species of Euplocamus and Ervilia which genera are not 
represented on the shores of S. America, all endemic forms show relations to 
the American fauna, above all to that of the Peruvian Province; only a few 
have their nearest allies in the Magellanic Province (such as Avicula aequivalvis) 
or in the southernmost part of the Peruvian Province (Onchidium juanfernan- 
deztanum), A northern origin is likely as regards Venerupis fernandeziana, the 
genus being represented by a second species occurring from Panama to N. Peru. 
The one of the endemic genera, Fuanella, speaks in favour of an origin 
from the southern part of the S. American coast (the closely allied 7yrznuna is 
established on a species from Calbuco), whereas the second genus, Aplyszopsis, 
lacks allies within the same districts, the genus Aplysia (= Tethys) occurring 
i. a. within the Peruvian Province and in the Pacific. 
The summary is, that the marine mollusc fauna of Juan Fernandez shows 
a closer relation to the American than to the Indo-Pacific one, and that the 
great quantity (50%) of endemic species indicates a long isolation. 
About the terrestrial mollusca of Juan Fernandez, which are by far more 
abundantly collected by the Swedish expedition than the marine ones, no — 
comprehensive report has been issued hitherto. There are only scattered de- 
scriptions and notes published on them. None has been made subject to a 
detailed anatomical investigation; our knowledge has been merely superficial, 
and their relation has been settled in a few cases only, above all by the works 
of PILsBRY (Man. of Conchology, ser. 2, vol. 9, 1894—95, and 21, I910—11), 
who also quotes the few authors having written on this subject. 
But for a few species (Agriolimax agrestis, Limax arborum, Milax gagates, 
Flelix aspersa, Hyalinia cellaria and alliarvia), which have been introduced in 
recent times, the terrestrial mollusca of Juan Fernandez are all endemic species. 
The islands have no species in common with other districts. There are indi- 
genous representatives of three families only, Endodontidae, Tornatellinidae, 
and Succineidae, all of great age comparatively; more recent and highly dif- 
ferentiated families, such as Helicidae, are entirely wanting in the original fauna. 
Of Endodontidae there is one endemic genus, Amphidoxa, closely related to 
Stephanoda, which is exclusively S. American (mostly in the south-western 
shore-parts of the Continent). The remaining genera, Punctum and Endodonta, 
are not at all represented in the Neotropical Region, the former being limited 
to the Northern Hemisphere, and the second to Australasia and Polynesia. The 
fam. Tornatellinidae comprises two genera endemic in Juan Fernandez, Yorna- 
tellina and Fernandezia; both show a remarkable relation to Pacific groups 
(the new genus Paczficel/a from Easter Island), and are also allied to the Hawaiian 
fam. Achatinellidae. Swccévea is a genus of world-wide distribution; the Juan 
Fernandez species seem to be allied partly to Pacific and partly to S. American 
forms, and Omalonyx, which seems closely related to certain Juan Fernandez 
species of Swccznea, has one of its representatives in these islands, the other 
one on the S. American Continent. 
By the Swedish expedition the following marine mollusca were collected 
(an asterisk signifies that they are previously recorded; cf. DALL): 
