62 The American Naturalist. [January, 
EMBRYOLOGY. 
Optimum Temperature for Incubation.—M. Féré contributes 
to the Journal de l Anatomie for July, 1894, the results of some ex- 
periments upon hen’s eggs incubated at 34°-41°. These seem to have 
been made with caution and to warrant the author’s conclusion that 
38° is the temperature at which the smallest number of abnormal de- 
velopments take place, at least during the first few days of incubation. 
By exposing eggs to fumes of alcohol the author finds also that the 
injurious effects are overcome afterwards, in a larger percentage of 
cases, if the eggs are incubated at this optimum temperature, 38°, than 
at any other. 
Cell Lineage.—Mr. A. D. Mead has made a comparative study 
of the cleavage in the polychetous annelids, Amphitrite, Lepidonotus, 
Clymenella and Scolecolepsis, along the lines marked out by E. B. 
Wilson in his noted paper upon Nereis. From the preliminary re- 
sults,’ those who are especially interested in this group may gather 
much of i importance regarding the exact fate of cells of equal origin in 
the different species. 
It will be of general interest to compare the results, when published 
in full, with those obtained upon Nereis, for in spite of the resemblances 
that are so close in this group there seem to be some marked differ- 
ences, in the axial relations especially. We note that the median 
plane of Amphitrite corresponds to a plane bisecting two of the first 
four cells in place of passing between two cells, right and left, as in 
Nereis. 
Fertilization in the Earthworm.’—A preliminary account of 
what promises to be a most valuable contribution is the result of the 
detailed study of the eggs of the striped earthworm, Allolobophora 
fetida. The author, Katherine Foot, has studied the processes of 
maturation and fertilization in some two hundred eggs taken from the 
cocoons in which they are laid. 
It seems that the sperm grows very rapidly just before the eggs are 
laid, so that one sperm may more than double its length within two 
1 Edited by E. A. Andrews, Baltimore, Md., to whom abstracts, reviews and 
_ preliminary notes may be sent. 
-~ 2 Journal of Morphology, ix, Sept., 1894. 
3 Journal of Morphology, ix, Sept., 1894. 
