AJS’D PLACENTA OF THE ELEPHANT. 
ill-success of guesses as to the nature of the foetal membranes, from the natural affinities 
indicated by any such kno^vn modification. Thus, as regards the Elephant itself. Sir 
Eveeaed Home wrote : — “ The mare has no placenta, only a chorion ; the period ” (of 
gestation) “ is eleven months. The Elephant, whose period is twenty-two months, 1 
have no doubt, from the appearance of the inside of the uterus, has no placenta, but a 
chorion*;” and the Elephant is classed accordingly with the Horse, Whale, Hog, and 
Camel f. 
The convictions as to the limited value of the placenta, in Mammalian Classification, 
wfrich were expressed and illustrated in the Hunterian Lectures for 1860, and were 
derived mainly from a study of the series of foetal structures in the Hunterian Physiolo- 
gical Collection, described in the concluding volume of the ‘ Catalogue ’ of that Collec- 
tion J, appear to me to be strengthened by the remarkable modifications of the placental 
structm’es of the Elephant, which form the chief subject of the present communication. 
Explanation of the Plate. 
PLATE XVI. 
Fig. 1. Chorion and placenta of the Elephant [Elephas Indicus)^ on the scale of 2 inches 
to a foot. 
a, a!. The chorion ; a!, the torn end from which the foetus had escaped. 
h. The annular placenta. 
c. The tract along which the foetal was connected with the maternal portion. 
iZ, d. The superficial Hllosity at the poles of the chorion. 
e. The allantoic corpuscles, seen through the exochorion. 
f. Umbilical cord. 
g. The urachus, before expanding into the allantois. 
Fig. 2. A portion of the \illous surface of the chorion, from the part marked d in fig. 1, 
of the natural size. 
Fig. 3. A portion of the allantois, Hewed from its amniotic surface, showing the cor- 
puscles of the natm’al size. 
* Tom. cit. p. 452. t ‘ Order 7,’ tom. cit. p. 503. 
J “Physiological Series,” vol, v. 4to, 1840, pp. 112—170. 
3 A 
MDCCCLVII. 
