1897.) Embryology. 169 
tive tissue mass; about this the epithelial cells are subdivided by a 
network formed from the radiating partitions and the leucocytes; the 
epithelial cells in the meshes of this network are much enlarged but 
not increased in number, division having ceased at the time of rupture. 
The yellow body is complete in from sixty to seventy-two hours. It 
is then much larger than the original Graafian follicle, as the epithelial 
cells are swollen to ten times their former size and are intertwined with 
the newly formed connective tissue bearing a rich network of capillaries. 
Later more or less fat is deposited in the epithelial cells and the body 
has a slightly yellow color, but here, as in some other mammals, the 
name is misleading. 
As far as the author's observations go the corpora lutea do not 
degenerate, in the mouse, but remain unchanged during the life of the 
animal and thus add much to the size of the ovary. 
Cleavage in Ovarian Eggs.—Professor J. Janosik’ finds in some 
follicles that atrophy in the rabbit and guinea-pig ovarian eggs may 
undergo a real cleavage, though of course there has been no fertiliza- 
tion (as far as known). Such ovarian eggs may form small cells very 
like polar bodies and lying near a true spindle which is in the position 
of a maturation spindle. This is more common in young than in old 
animals, 
There are cases of true cleavage with few to many nucleated cells and 
these cells may be of equal size or some large and some small. There 
are also cases of “ fragmentation ” where the isolated masses of proto- 
plasm contain no visible nucleus. In these cases of ovarian cleavage 
the membrana pellucida disappears as it does in the normal cleavage. 
Such eggs later atrophy with their follicles. 
PSYCHOLOGY: 
Annual Meeting of the American Psychological Associa- 
tion.—The Fifth Annnal Meeting of the American Psychological As- 
sociation was held at Boston and Cambridge, on December 29 and 30, 
1896. The step taken a year ago of affiliating with the American 
Society of Naturalists proved so successful that this course has been 
adopted permanently by the Association. At the present meeting 
® Archiv. f. Mik. Anat., 48, Nov. 7, 1896, pps. 169-181. 
! Edited by H. C. Warren, Princeton University, Princeton, N. J. 
