366 A. A. W. HUBREOHT. 
Fleischmann’s researches on the placenta of Carnivora (A. 
Fleischmann, ‘Embryologische Untersuchungen,’ Hft. 1; 
‘Untersuchungen iiber einheimische Raubthiere,’ 1889) tend to 
show that, in many respects, the facts there observed should 
have a place to themselves, as was before indicated for Rodents 
and Ungulates. An undeniable disappearance of the maternal 
epithelium is strongly insisted upon by Fleischmann ; but of a 
special proliferation of trophoblast no traces seem to exist, as 
far as I can judge by the figures. 
The peculiar arrangement of the maternal crypts from 
which the epithelium disappears, interlocking with allantoic 
villi, seems fully to counterbalance the necessity of the inter- 
vention of a thickened, or in any way differentiated, tropho- 
blast layer in the formation of the placenta. For all these 
reasons I will not bring the Carnivora for the present into any 
closer comparison. 
Another very recent contribution to the literature of the 
subject is a short paper by Strahl with one plate : “ Untersuch- 
ungen iiber den Bau der Placenta. I. Die Anlagerung des 
Hies an die Uteruswand ” (‘Archiv fiir Anat. und Phys. Anat. 
Abth.,’ 1889, p. 213). He therein treats the rabbit, the mole, 
and the dog. His figures of the first and of the last-named of 
these mammals are less definite than those of Masius and 
Fleischmann. 
The disappearance of the uterine epithelium in certain Car- 
nivora, so strongly insisted upon by the latter author, is not 
admitted by Strahl. As to the rabbit, his interpretation is 
wholly divergent from the one advocated by Masius. The 
trophoblastic tissue which was above referred to, which van 
Beneden and Julin (‘ Archives de Biologie,’ vol. v, p. 402, pls. 
xxi and xxiv) described in its earliest horseshoe-shaped form, 
which was called by Kolliker the “Ektodermawulst,” and which 
Masius traced both in its origin and in its further develop- 
ment and significance for the placentation process, is stated 
by Strahl to be a derivate of the proliferating uterine epithe- 
lium. This is said to spread over the surface of the blastocyst, 
radiating from two points where blastocyst and uterine wall 
