466 A. E. Verrill on the Mollusca of Europe and N. America. 
familiar with American than with European shells. But as the 
redgings in connexion with the investigations of our fisheries 
_by the U. S. Fish Commission were under my superintendence 
during the two past seasons, and Mr. Jeffreys alludes to the 
fact (though rather indefinitely) that he, by invitation of Pro- 
essor Baird, accompanied us on several dredging-excursions in 
1871, it seems necessary that I should point out some of the 
more important of these errors, lest it be supposed by some 
that the same views are held by me. : 
It is not my intention to discuss at this time the numerical 
results presented by Mr. Jeffreys; * but I would remind the 
readers of his article that the regions compared are in no respect 
similar or parallel, and that it is scarcely fair to compare the 
shells from the entire coast of Europe with those from about 
200 miles of the coast of New England, where the marine 
climate is for the most part more arctic than that of the extreme 
north of Scotland—and, moreover, that the last edition of 
Gould’s “Invertebrata of Massachusetts” contains only a part 0 
the species added to our fauna since the first edition was pub- 
lished in 1841, and very little of the great mass of facts m 
regard to distribution, &c., which have been accumulated by 
merican naturalists during the last thirty years. Conse- 
quently that work is far from being a good “standard of com- 
parison.” To make a just comparison, all the shells on our 
coast, from Labrador to Florida, should be compared with those 
of Europe. : 
And without going into a long discussion of his peculiar 
views on the geographical distribution of our shells, I would 
remark that, to an American, it seems rather singular that most 
writers, whether zodlogists or botanists, find 1 
necessary to trace back to a European origin all the existing 
species of this country, and to suppose that they have “mal 
grated” from Europe to America and other countries in spite 0 
opposing currents and all other obstacles, Thus Mr. Jeffreys 
plants connecting the Tertiary and Cretaceous ages with the 
_ present; that many of these supposed European forms (whether 
rial or marine) can be traced back into our Tertiary f 
4 
3) bo a 
aS quite as far (if not farther) than they can in Burope; amd 
