282 BULLETIN OF THE MUSEUM OF COMPARATIVE ZOOLOGY. 
But assuming that both are at hand, —a very detailed knowledge and 
a very complete collection, — it is obvious that at the present time both 
can exist only for some specialty, and not for the whole class of insects. 
Every attempt to go beyond those limits commonly entails errors 
in a geometrical progression.  Undoubtedly the smallest fragment of 
an insect belonged to a species, to a genus, to a family. Nevertheless 
it cannot be an advantage to science, it cannot mark a progress for sci- 
ence, if such fragments are named and determined as a species, and as 
possibly belonging to such and such a genus and family. It is evident 
from the “insignificant fragment" of Dyscritus vetustus, discussed at 
length in page 22, that any scientific judgment, and therefore any scien- 
tific classification of it is impossible. It can belong to several differ- 
ent families, and it is quite as probable that it belongs to Platephemera, 
or to Gerephemera, or to some entirely different insect. The fragment is 
so insignificant, that, if the whole fauna of the Devonian Insects was 
known, it would be impossible to ascertain its place with certainty. 
Therefore such names are not only useless, but a hindrance to science. 
Ten years ago the Rev. Mr. Eaton, of Croydon, England, expressed the 
same opinion in strong terms; but Mr. Scudder (p. 11) objects to these 
strictures in the most emphatic manner, without giving any satisfactory 
reasons. 
Paleontological works are and can only be studied and understood in 
our days by specialists, and for special groups. Others must take the 
conclusions for granted, which they are not able to control, for want of 
special knowledge. I must frankly declare that it is for the interest of 
science that such nomenclature should be discontinued, as it is sure to 
be with a little knowledge of facts. 
CAMBRIDGE, March, 1881. 
