1835.] DISTRIBUTION OF THE SHELLS. 391 
species not yet specifically examined, of Trochus, Turbo, Mono- 
donta, and Nassa. He has been kind enough to give me the 
following interesting results: of the ninety shells, no less than 
forty-seven are unknown elsewhere—a wonderful fact, consider- 
ing how widely distributed sea-shells generally are. Of the 
forty-three shells found in other parts of the world, twenty-five 
inhabit the western coast of America, and of these eight are dis- 
tinguishable as varieties ; the remaining eighteen (including one 
variety) were found by Mr. Cuming in the Low archipelago, and 
some of them also at the Philippines. This fact of shells from 
islands in the central parts of the Pacific occurring here, deserves 
notice, for not one single sea-shell is known to be common to 
the islands of that ocean and to the west coast of America. The 
space of open sea running north and south off the west coast, 
separates two quite distinct conchological provinces; but at the 
Galapagos Archipelago we have a halting-place, where many 
new forms have been created, and whither these two great concho- 
logical provinces have each sent several colonists. ‘The Ame- 
rican province has also sent here representative species; for 
there is a Galapageian species of Monoceros, a genus only found 
on the west coast of America; and there are Galapageian species 
of Fissurella and Cancellaria, genera common on the west coast, 
but not found (as I am informed by Mr. Cuming) in the central 
islands of the Pacific. On the other hand, there are Galapa- 
geian species of Oniscia and Stylifer, genera common to the West 
Indies and to the Chinese and Indian seas, but not found either 
on the west coast of America or in the central Pacific. I may 
here add, that after the comparison by Messrs. Cuming and Hinds 
of about 2000 shells from the eastern and western coasts of Ame- 
rica, only one single shell was found in common, namely, the 
Purpura patula, which inhabits the West Indies, the coast of 
Panama, and the Galapagos. We have, therefore, in this quarter 
of the world, three great conchological sea-provinces, quite dis- 
tinct, though surprisingly near each other, being separated by 
long north and south spaces either of land or of open sea. 
I took great pains in collecting the insects, but, excepting 
Tierra del Fuego, I never saw in this respect so poor a country. 
Even in the upper and damp region I procured very few, except- 
ing some minute Diptera and Hymenoptera, mostly of common 
