HKMKI.I.irAliors ASh Mf l.Tl I'.l i;i its l'i;h:ilXA\cy. 



1 •;.' 



maternal placenta, which, of course, causes an interruption to the cir- 

 culation of the younj^ animal, and a suspension of nourishment and 

 oxygenation of its blood. 



In the second variety of gestation, in which the chorion is connnon 

 to the two f(rtuses, but which are yet separated by the amnion, there 

 is only one placenta ; the two having a circulation in common, tlu-ougli 

 their placenta* and the umbilical vessels connnunicating l)y their vascu- 

 lar ramifications. In this case the expulsion of one fcrtus necessarily 

 brings about that of the other. This also occurs when both are con- 

 tained in tile same envelopes. 



I believe only two instances are on record of inclusion : that of the 

 first mentioned variety, in which one fcetus was found in the abdominal 



Fig. ti6. 



Twi.N pKKtiNANCY : CoW. 



cavity of the other, Bartholin, the celebrated anatomist, at the com- 

 mencement of the seventeenth century described the case of a Mare 

 which brought forth a Mule, in the abdomen of which was found an- 

 other : and Gurlt' mentions an instance in which one fcrtus was 

 developed within the abdominal cavity of a Calf, and consisted of an 

 incomplete left hind leg, a membranous organ representing the uterus, 

 and the skin and some vessels. It may be remarked, however, that 

 Rainard witnessed an instance of this abdominal inclusion in a Goose. 

 The egg was double tlie ordinary size, and it had another inside of 

 about the ordinary dimensions ; each had a perfectly formed shell. - 

 The subcutaneous tumours of young animals, containing either a whole 

 foetus or portions of a pre-existing one, are connnon, 



' .\fagazin/iir rhifrheilhinde, 1860. p. 347. 



• In the Vfhrinanj Journal for 1891 (p. 88), Mahon de«crib<'«< an iriHtanw of inclusion 

 in a male Hare. 



