APPARATUS OF THE ELEPHANT. . 419 



outer of which seems to represent part of the allantois. On the other hand, while 

 it is impossible to distinguish the chorionic layers, nevertheless it will be seen that 

 the branches of the umbilical arteries and veins lie upon the inner or foetal surface 

 of the chorion, and that they pass over the chorionic surface of the cotyledons. 

 Now, Prof. Owen states that in his specimen these cotyledons (PI. 49, z, z, z) 

 adhered to the "allantoic side of the sheath of the vessel," and that "the coty- 

 ledons belonged entirely to the latter membrane;" that is, the allantois, after this 

 had been removed from the chorion. This confirms what an examination of my 

 specimen led me to suppose, namely, that the vessels and cotyledons lie between 

 two layers : the outer one, the chorion and vascular layer of the allantois ; the 

 inner, the mucous layer of the allantois — all three being fused into one in my 

 specimen. If this view be correct, the elephant in utero would be inclosed, 

 first by the amnion — then there would be a space ; and, secondly and externally, 

 by the chorion. The allantois would exist only as a distinct sac in the earlier 

 periods of pregnancy. The same will hold true of the umbilical vesicle, of which 

 I did not find a trace. Prof. Owen tells us that he counted one hundred and 

 twenty cotyledons in his specimens. There are over two hundred and fifty in 

 mine, varying from half an inch to over an inch in length.* I noticed about a 

 dozen in the amnion, which also confirms the view ofi'ered of its having two layers. 

 These bodies seem to be fibrous in structure, with some inter-fibrous granular mat- 

 ters. As to their morphological or physiological import I have nothing to ofi'er. 



The umbilical cord is three inches in diameter and fifteen inches in length, 

 measured from beginning of umbilical vein to where it divides into two branches 

 (PI. 48, d). It consists of two arteries and one large vein, held together by 

 the usual connecting tissue (PI. 48, d). The main vein divides into two, which 

 attain a length of about twenty-two inches before reaching the outer border of the 

 placenta (PI. 49, d, d'"). The outside artery, double the size of the innermost one, 

 divides into two branches, which accompany the branches of the vein to the outside 

 of the placenta (PI. 49, d,d"'). The umbilical vein, ten inches above its bifurca- 

 tion, gives off a slender branch (PI. 49, d', d"), which bifurcates six inches below 

 its origin, and passes to the middle parts of the placenta. The small umbilical 

 artery divides into two branches, which accompany the small umbilical veins to 

 middle of placenta (PI. 49, d', d"). There are, therefore, two large and two small 

 main arteries, and two large and two small main veins. The manner in which these 

 vessels are situated in the placenta is sufficiently apparent from the figures. 



* I find them usually in the vicinity of the placenta and along the course of the longest vessel. 



