298 THE ORNITHORHYNCHUS. 



and being skinned while yet warm, it was observed that milk 

 oozed through the fur on the stomach, though no teats were 

 visible on the most minute inspection j but on proceeding with 

 the operation, two canals were discovered containing milk, and 

 leading to a large glandular apparatus." The existence of milk 

 in the situation described, fully confirms the correctness of the 

 deduction made by Professor Owen,* from the minute dis- 

 section of several specimens, that the glands discovered by 

 M. Meckel are really mammary, as this author had previously 

 asserted. The professor's dissections, however, though they 

 established the existence of numerous minute tubes leading 

 from the glands in question through the skin, where it was 

 covered with wool, did not enable him to detect any canals 

 so large as Lieutenant Maule describes. These canals, however, 

 as has been recently ascertained by minute dissection, are not 

 single 5 but on each side there is a bundle of small capillary 

 tubes, united so as to form a short cord; these fine tubes 

 open in a dark coloured circle on the skin, but which is 

 covered by the fur, the glandular mass from which they pro- 

 ceed being of large size, compressed, extending nearly the 

 whole length of the body, and lying immediately beneath the 

 skin. From the preceding collective evidence, as well as from 

 some circumstances connected with its anatomy, it seems 

 certain that the ornithorhynchus is ovo-viv iparous ; that the 

 young are indeed hatched from eggs, but hatched before their 



* Philosophical Transactions (1832). In the same celebrated publication 

 (1834), Professor Owen has demonstrated the co-existence of the chorion and 

 the vitelline membrane in the ovum, or egg of the ornithorhynchus ; and this 

 fact has been further established by the more recent researches of Krause (in 

 M tiller's Archiveri), and of Mr. Wharton Jones (in the Philos. Trans. 1837). 

 With the structure of this ovum, the ova of the batrachian reptiles present 

 a close analogy, being inclosed by both a vitelline membrane and an external 

 gelatinous chorion : and in the Triton, the latter of these acute observers has 

 noticed, that when the embryo has attained a certain size, but still at an early 

 period, the vitelline membrane is ruptured, and the embryo, with its amnios 

 and umbilical sac, is then immediately invested by the chorion. This curious 

 phenomenon of the destruction of the vitelline membrane seems to afford a 

 key to the true analogies and relations of the mammiferous chorion. 



