STUDIES IN MAMMALIAN EMBRYOLOGY. 393 
DESCRIPTION OF PLATES XV—XXVII, 
Illustrating Prof. A. A. W, Hubrecht’s paper “ Studies in 
Mammalian Embryology.” 
PLATE XV.) 
Figs. 1—3.—Three diagrammatic sections of the uterus of Erinaceus. 
(These sections are here represented of the same size, whereas in reality the 
section Fig. 2 is larger than that of Fig. 1, and Fig. 3 again considerably 
larger than Fig. 2.) 
mes. Mesometrium. MM. Muscularis. art., v v., and v. Arterial and venous 
blood-vessels. 7. The lumen of the uterus. g/. The glands in the mucosa, 
considerably reduced in Figs. 2 and 3. ca. Blood-spaces in the decidual 
swelling. 2, The embryo. ZS. The trophosphere. 77. The trophoblast. 
ep. Epiblast of the germinal area. Ay. Hypoblast. 
Fig. 1 is the section through the uterus of a hedgehog in an early stage 
of pregnancy, at a spot between two spherical decidual swellings. 
The mucosa has retained its normal aspect as in the non-pregnant 
uterus. The darker shading of the central part of the mucosa close 
to the uterus lumen is meant to indicate that in this region the 
connective-tissue cells are much closer together than in the outer region 
between this and the muscularis. The blind ends of the glands are 
more or less coiled. They are much shorter close to than opposite the 
mesometrium. The blood-vessels take a circular course, giving off 
finer vessels in a radial direction. 
1 The following figures—as far as they are not diagrams—have been drawn 
with the camera from preparations preserved in canada balsam. In order to 
facilitate a later critical comparison of the results arrived at in this paper and 
figured on the following plates, I have indicated for the more important figures 
the catalogue number of the preparation from which that figure was taken. 
As these preparations are systematically arranged in the Utrecht Zoological 
Museum, and as most of the stages are there represented by very numerous 
specimens, | am prepared to hold such preparations at the disposal of any 
original investigator who might express the wish to compare the sections here 
figured and described with his own. 
