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XVII. — On the Placentation of Halicore Dugong. By Sir Wm. Turner, M.B., LL.D., 

 D.C.L., F.R.SS.L. and E., Professor of Anatomy in the University of Edin- 

 burgh. (Plates L, II., III.) 



(Read 1st July 1889.) 



Comparative anatomists have long desired detailed information on the placentation 

 of the Sirenia. It is true that in 1878 Dr Paul Harting presented to the University of 

 Utrecht a graduation thesis,* in which he described the foetal membranes and foetus of a 

 Dugong, which had been acquired a short time before for the Zoological Museum of that 

 University. The specimen had been preserved for many years in spirit of wine, and had 

 apparently been collected by a surgeon to a merchant ship. The foetus was 2 7 '8 centi- 

 metres (11 inches) long. The entire chorion, with the exception of the two poles and 

 their immediate vicinity, was covered by densely packed, short and but little branched 

 villi, and Dr Harting came to the conclusion that the placenta of the Dugong was 

 diffuse and non-deciduate. 



Dr Harting's description and drawings, though satisfactory as far as the material at 

 his disposal would admit, were incomplete, owing to the absence of the uterus. The small 

 size of the foetus, in relation to the magnitude of the adult animal, also made it possible 

 that the diffused arrangement of the villi over so large a part of the surface of the 

 chorion represented an early stage in the placental formation in this animal, and that 

 some modification might arise in a later stage of intra-uterine development. I have, 

 accordingly, been very desirous to acquire the gravid uterus of the Dugong, and if possible, 

 at a more advanced stage of gestation than in the Utrecht specimen. In my endeavours 

 to obtain such a specimen, I was fortunate to enlist the sympathy of my friend and former 

 pupil Dr Anderson Stuart, Professor of Anatomy and Physiology in the University 

 of Sydney, N.S.W.; who, on hearing that C. W. de Vis, Esq., M.A., the Curator of 

 the Queensland Museum, Brisbane, had a gravid uterus of the Dugong in his possession, 

 which he had received from the Moreton Bay fishers, wrote to ask if it could be sent to 

 me. Mr de Vis with the greatest courtesy acceded to this request, and the specimen 

 reached me in good order in the month of May of the present year. I wish to express 

 my indebtedness to Mr de Vis for having so generously placed at my disposal a specimen 

 of so much rarity and value. 



The gravid uterus had been preserved in spirit sufficiently strong to have kept it in 

 good condition, but not so concentrated as to needlessly contract the tissues. With the 

 exception of two or three cuts of no great size, it was uninjured, though the Fallopian 

 tubes had been divided, and the ovaries cut off in taking it out of the abdomen. 



* Het Ei en de Placenta van Halicore Dugong^ Proefschrift, 18th February 1878. Utrecht. 

 VOL. XXXV. PART II. (NO. 17). 5 L 



