feeling of distrust in
the worthiness and truth of the views which I had to present.

There is certainly no occasion to apologise for not having quoted
my paper. The law of acceleration and retardation of development was
therein used to explain the appearance of other phenomena, and might, as
it did in nearly all cases, easily escape notice.

My relations with Prof. Cope are of the most friendly character; and
although fortunate in publishing a few months ahead, I consider that
this gives me no right to claim anything beyond such an amount
of participation in the discovery, if it may be so called, as the
thoroughness and worth of my work entitles me to...

The collections which I have studied, it will be remembered, are fossils
collected without special reference to the very minute subdivisions,
such as the subdivisions of the Lower or Middle Lias as made by the
German authors, especially Quenstedt and Oppel, but pretty well defined
for the larger divisions in which the species are also well defined.
The condition of the collections as regards names, etc., was chaotic,
localities alone, with some few exceptions, accurate. To put this in
order they were first arranged according to their adult characteristics.
This proving unsatisfactory, I determined to test thoroughly the theory
of evolution by following out the developmental history of each species
and placing them within their formations, Middle or Upper Lias, Oolite
or so, according to the extent to which they represented each other's
characteristics. Thus an adult of simple structure being taken as the
starting-point which we will call a, another species which was a in
its young stage and became b in the adult was placed above it in the
zoological series. By this process I presently found that a, then a b
and a b c, c representing the adult stage, were very often found; but
that practically after passing these two or three stages it did not
often happen that a species was found which was a b c in the young and
then became d in the adult. But on the other hand I very frequently
found one which, while it was a in the young, skipped the stages b and
c and became d while still quite young. Then sometimes, though more
rarely, a species would be found belonging to the same series, which
would be a in the young and with a very faint and fleeting resemblance
to d at a later stage, pass immediately while still quite young to the
more advanced characteristics represented by