248 
the connective tissue cones of the villi are modelled since the epi- 
thelium had fallen off to a very great extent. In general the appear- 
ance of the villi is much 
like that found in an em- 
bryo pig of 85 mm long., 
Fig. 1. 
It remains for me to 
discuss the order of the 
appearance of the folds and 
villi in the different portions 
of the same intestine, and 
then to compare the in- 
testines of the various em- 
bryos. In order that this 
could be done in an intelli- 
5 € gent and systematic manner, 
(he N > OU use was made of models of 
N“ me Cc \ / the intestine of these em- 
ae Wa WAG bryos. For comparison the 
RN 7 NN fey 
NEN 3207, / EN reader may refer to thedraw- 
ME ings of these models given 
5 ER, 7 in Hıs’ Archiv, 1897, Supple- 
NR ment. In my description I 
| shall designate the loops 
/ intestine of a human embryo(XXXIV) 
80 mm long, multiplied 55 times. 
| er / Fig. 6. Reconstruction of the 
from above downward by the figures 1, 2, 3, etc., as Dr. MALL’s 
figures are also marked. 
The inner wall of the intestine of embryo IX is smooth throughout 
its entire extent. In embryo VI there are five or six longitudinal folds 
in the upper part of the intestine, marked 7 in the figures just re- 
ferred to. Lower down, region 2, the folds are not as large nor as 
numerous. Region 3 is pictured in Fig. 3. From now on the folds 
diminish greatly as in region 4; and at the point of juncture between 
regions 4 and 5 the folds disappear entirely. In regions 5 and 6 
there are no folds, the epithelial lining of this portion of the intestine 
being perfectly smooth, giving much the appearance of that of em- 
bryo IX, Fig. 2. The study of the successive regions in embryo 
No. XLV showed the following: 
