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Anatomy. ''Tfw foeful nn'inln-aiK'.s 1111(1 the phicentd of P/ioca 



vihi/ina." By A. J. 1'. van dk\ IIrokk. (('oiniiiiuiicjiled by 

 Piof. T.. BOT.K). 



((lommunicated in Ihe meeting ol' January 30, 1904). 



Some time ago a seal in an advanced state of gestation was sent to 

 the anatoniical Laboratoi-v of the Amsterdam llniversity. As neither 

 the foetal envelopes nor the placenta of the ])innepedal carnivores have 

 been described in detail, 1 was very gralilied to be enti-nsted by the 

 Director of the Laboratory with the task of carefnlly examining these 

 organs. The ])rei»aration (nrned ont to be in very good condition and 

 well enough i)reserved for microscopic examination. 



Whereas a more detailed description will be published in another 

 place, the following may be given here as the principal results of 

 my investigations. 



The gravid uterus was U-shaped, tlie convexity l)eing on the cranial 

 side. The oi'gan, which Avas somewhat flattened dorso-ventrally was 

 lying in transverse <lirection, so that the fundus uteri was situated 

 in the righthand part of the body. This U-shaped curve was ac- 

 companied by a twisting oï the organ, so that the left ovarium, 

 entirely enveloped by an ovarial bag, was medially situated. 



The greater part of the ligaiuentum latum had l)ecome absorl)ed; 

 the ligamentum rotundum, a very powerful cord, ran from the front-, 

 respectively hind-wall of the uterus, that is : from the spot where 

 the ovarium was lying against the uterine wall, running down in a 

 slanting direction across the latter, towards the abdominal wall. The 

 ostium uteri, tilled with a mucous clot, showed an aperture of d= 3 cm. 



Close to the top of this ostium, which formed an oval foramen in 

 the middle of the portio vaginalis, the foetal sac, rather strained, 

 could be felt. All this seemed to indicate that the animal, being in 

 labour, had gone ashore, when it was caught. 



On opening the uterus by means of a longitudinal incision in the 

 organ, along the convexity, the following was noticed : The wall of 

 the uterus is extremely thin in jiroportion to the voluminous organ, 

 a little more than 1 mm., but increases in thickness towards the 

 vagina. The nmscularis of the wall of the latter, however, is rather 

 thick (1 cm.). 



The chorion, as well as the placenta, is only loosely attached to 

 the walls of the uterus all over. It appears that the foetal sac reaches 

 down to the ostium uteri. On detaching the placenta I found septa 

 of cellular tissue adhering to the inner surface of the wall of the 

 uterus, which, just there, is somewhat thicker. 



