292 PROFESSOR TURNER ON THE 
younger ovum already described, and on looking down the larger pits their sub- 
division into smaller crypts could be seen. The crypts were lined by an epithelium, 
numbers of the cells of which possessed a columnar form, though others were 
swollen and otherwise altered in shape, so as to be irregularly polygonal. The 
cell protoplasm was granular and the nucleus was distinct. The sub-epithelial — 
connective tissue was vascular. When vertical sections were made through the 
placental area, the more dilated size of the crypts and pits, than in the younger 
specimen, was distinctly recognised, being thus in conformity with the larger 
size of the chorionic villi. Between the deeper closed ends of the crypts and 
the muscular coat was a definite layer in which portions of gland tubes, lined by 
an epithelium, some of which were transversely, others obliquely divided, could 
be seen. The glands were dilated as in the younger specimen, and not so 
numerous as the crypts, neither could I obtain satisfactory evidence of the com- 
munication of the mouths of the glands with the crypts. I am led therefore to 
the conclusion that the crypts formed in the early period of gestation in the 
placental area of the cat are not due to a mere widening of the mouths of the 
tubular glands, but are produced in the same manner in this animal as I have 
satisfied myself to be the case in the gravid uterus of the pig and mare, by a 
great increase in the amount of the interglandular part of the mucosa, which 
becomes folded, so as to form the crypt-like arrangement which I have just 
described. In this respect, therefore, my observations agree with those of 
Professor ERCOLANI on the same animal.* 
The interpretation, therefore, which ErcoLani and I have put on the appear- 
ances seen in the placental area of the cat in the early stage of gestation, differs 
from that given by Dr SHArpey of the appearances seen in the uterine mucosa 
of the bitch at a similar stage. As is so well known, Dr SuHarpey held that the 
pits and “cells” (crypts) seen on the inner surface of the uterus, which receive 
the villi of the chorion, are the mouths of the utricular glands enlarged and 
widened. It is possible that in the cat as in the Orca,t the utricular glands 
may open into some of the crypts, so as to seem to justify the inference that 
they were formed by a widening of the mouths of the pre-existing glands. But 
this interpretation obviously cannot be given of the formation of those crypts ~ 
which are interglandular in position. Hence it seems to be more in conformity 
with the structural arrangements of the organ to conclude that the crypts which 
arise in the uterine mucosa during pregnancy are new formations, produced by 
a great hypertrophy and folding of the surface of the mucous membrane. 
When the ovum of a cat, which had completed about one-half the period of 
gestation, was examined, a most important advance in placental formation was 
observed. The zonary villous band on the chorion was restricted to its middle 
* Mem. dell Acad. delle Scienze di Bologna, 1870. Plates 2, 3, 4. 
+ See my Memoir in Trans. Roy. Soc. Edinburgh, 1871. 

