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XVI. Descrijption of the Foetal Membranes and Placenta of the Elephant (Elephas Indi- 
cus, Cuv.), with Remarks on the value of placentary characters in the classification 
of the Mammalia. By Professor Owen, F.R.S. 
Received AprU 14, — Read May 14, 1857. 
Seba gives a figure of the foetus of an Elephant in tab. iii. vol. i. of his great ‘ The- 
saurus but a knowledge of the foetal membranes of this remarkable quadruped has 
long been a great desideratum in both physiology and zoology. 
From the period of my appointment to the Hunterian Professorship of Physiology at 
the Eoyal College of Surgeons, London, in 1836, I lost no opportunity of urging this 
desideratum upon the attention of correspondents in Ceylon and India ; and, after some 
years, I had the gratification to receive a letter from Dr. Mokton, an accomplished Army 
Medical Officer quartered in Ceylon, stating that he had forwarded to me the membranes 
of a foetal Elephant, addressed to the Museum of the Royal College of Surgeons. On 
the arrival of this specimen in a keg of arrack, I prosecuted as complete an examination 
as the condition of the parts would permit, and made the preparations (Nos. 3558 c. and 
3558 D.), which are now in the Physiological Series of that Museum. The results of this 
examination were orally communicated in the Theatre of the College, in the 17th Lec- 
ture of my Course “ On the Generation and Development of the Vertebrate Animals,” 
dehvered in 1850 f; and were illustrated by diagrammatic views of the chief peculiarities 
which the parts presented. Circumstances prevented further publication of the facts at 
that time ; but I am now able to submit the following description of the foetal mem- 
branes and placenta of the Elephant to the Royal Society. 
The chorion of the Elephant (Plate XVI. fig. 1, a, d)., at about the middle of 
the period of utero-gestation, forms a transversely oblong sac, 2 feet 6 inches in long 
diameter, and 1 foot 4 inches in short diameter, encompassed at its middle part by an 
annular placenta [h, h), 2 feet 6 inches in circumference, varying from 3 to 5 inches in 
breadth, and from 1 to 2 inches in thickness. This placenta is partially divided by 
opposite constrictions into two moieties, one measm'ing 12 inches, the other 10 inches 
in length, and the extreme breadth being 5 inches in each ; the connecting isthmus is 
3 inches in breadth. The placenta presents the same spongy texture and vascularity as 
does the annular placenta of the Hyrax and of the Carnivora ; but the capillary filaments 
or villosities enclosing the foetal vessels enter into its formation in a larger proportion, 
* Locupletissimi Rerum naturalium Thesauri accurata Descriptio, &c., 4 vols. fol. Amst. 1734 — 1765. 
t “Foetal membranes of the Hog- and Horse-tribe : foetal membranes and placenta of the Hyrax and 
Elephant.” Printed Synopsis, 1850. 
2 z 2 
