342 Agassiz on the Embryology of the Turtle. 
Art. XXIX.—Recapitulation of the “Embryology of the Turile,” 
as given in Professor Agassiz’s “‘ Contributions to the Natural His- 
tory of the United States of North America,” Vol. II, Part IIT; 
by H. James Ciark, of Cambridge, Mass. 
THE following summary, of the “ Embryology of the Turtle,” 
was undertaken at the request of Professor J. D. Dana, one of 
the editors of this Journal. For certain reasons, given below, 
it will be seen that neither comment nor criticism upon the work 
is in place here. The method adopted in writing out this sub- 
ject, as it stands in the original work, is so far from the aphoristic 
style that I find it will be next to impossible to make extracts, 
which will give the pith of the matter, without inserting here a 
great portion of the whole. On this account I shall be compelled 
to rewrite, whatever may be presented, in a condensed form, 
with perhaps here and there a short extract. 
Had it not fallen to my lot, as Professor Agassiz’s assistant, 
to write out the embryological portion of these ‘‘ Contributions 
I would not have dared here to take the liberty of reconstruct: 
ing the fabric of the story of the development of the Turtle. 
As it is, it will not be possible, for want of room, nor really 
necessary, to render account of the whole history as originally 
written, but I will confine myself mostly to what is new im this | 
department of science. I 
ne te 7 1] 
~ oxi thelealancape Tied i Septic a natural a condition 
the egg, “a young animal was resorted to on account 0 
greater abundance of the smallest sized eggs and also 
the ovary is less opaque than in the adult.” a 
The origin of the egg—The ovary was cut out entire — 
floated in serum, so that the eggs might not be distorted b ee 
sure nor by pulling and tearing in order to get them un mah 
microscope. In the first place a comparative view was t n 3 
the whole mass of the eggs, from the youngest to the © a 
with a low magnifying power, and in this manner a ra - ep i 
was —_ of the respective condition of each es ea e 
prepared in part, by anticipation as it were, to 
comprehend Be cle of the phase of any one to that of any 
other or of the whole. 
