1901.] Nj^TURAL sciences of PHILADELPHIA. 367 



observed enclosed iu a coiumou chorion by Kolliker" before, and 

 by Duges" after Milne -Edwards' observations. Different explana- 

 tions have been offered by anatomists of this apparent anomaly of 

 one chorion enclosing a number of foetuses. The most satisfac- 

 tory as yet offered, though hypothetical, the early development of 

 the armadillo being unknown, is that originally the number of 

 chorions correspond to the number of foetuses, but that as devel- 

 opment advances the adjacent walls of the primitively distinct 

 chorions fuse together and ultimately break down, the result being 

 the formation of one chorion. In the case of the six-banded arma- 

 dillo, Dasypus sexdnctus, the mother gave birth to but one young, 

 and there were no reasons for supposing that more than one was 

 developed during the pregnancy. 



The young armadillo (Plate XVIIl, fig. 1), the fu'st born at the 

 Philadelphia Zoological Garden, a aiale which lived but a few 

 hours, was perfectly developed and measured from snout to end of 

 tail 25 centimeters (10 inches). The most striking feature of the 

 young animal externally was the size of the penis, it measuring 3.7 

 centimeters (1.5 inches). It is well known that this organ attains 

 an enormous size in the adult armadillo, absolutely as well as 

 relatively. Six distinct broad bauds and two indistinct narrow 

 ones were observed on the dorsal surface, but they were as yet soft 

 to the touch. 



No trace was found of an umbilical vesicle, amnion, or any 

 part of the chorion except that entering into the formation of the 

 placenta. The umbilical cord measured 22.5 centimeters (9 

 inches), the vessels not being spirally disposed, as was also observed 

 by Milne-Edwards to be the case in the Tamandua. The umbilical 

 vessels were so much torn (having been apparently gnawed l)y the 

 mother) as to make it impossible to inspect the placenta through 

 them. A mixture of gelatine and carmine was, however, forced 

 directly into a few of the small vessels of the placenta, which 

 consisted of the villous processes of the chorion only, without 

 admixture of any maternal tissue, and was therefore nou-decidu- 

 ate. The foetal villi were disposed as a girdle or zone (Plate 

 XVIII, fig. 2) on that part of the chorion in contact with the 



* EnhoicklungsgescMchte des McnscJien, 1879, S. 362. 



' Annales des Sciences KafnreUes, Sixicme Ser. , Zoologie, IX, 1879-80, p. 1. 



