OF THE ORNITHORHYNCHUS PARADOXUS. 
521 
approaches still nearer than the Marsupiata to Birds and Reptiles, its mode of 
generation may be in a proportionate degree analogous*.” 
For an animal possessing mammary glands he claims, however, the right to 
rank with the Mammalia ; and accords with Professor Geoffroy only so far 
as to consider the Monotremata a distinct order of quadrupeds, which he 
places, as in the system of Cuvier, next to the Edentata. 
Notwithstanding the authentic and circumstantial manner in which this 
discovery was given to the world, it has been by no means universally re¬ 
garded as conclusive with respect to the mammiferous nature of the Monotre¬ 
mata. Professor Geoffroy, having subsequently had an opportunity of dis¬ 
secting a female Ornithorliynchus, and of verifying in some measure the de¬ 
scription above quoted, has more especially endeavoured to invalidate the 
inferences drawn from it. He urges -f~, that the subcutaneous abdominal 
glands considered by Meckel as mammary, possess none of the characters 
of a true mammary gland;—that he examined them with the greatest attention, 
comparing them with the human mammary glands, and especially with those 
of marsupial animals, and that they were of a totally different texture ( tissu ), 
consisting of a vast number of caecums placed side by side, all directed to 
the same point of the skin, where only two excretory orifices were to be per¬ 
ceived, and these orifices so small, that the head of the smallest pin could 
not be made to enter them ;—that, above all, there was no trace of nipples ;— 
that in the specimen he examined, which had the size and appearance of an 
adult female Ornithorliynchus, the apparatus in question was not more than a 
fourth part of the size of that observed by Meckel. But a mammary gland, 
he further observes, when arrived at its full development, occasions an en¬ 
largement of all its constituent parts, the nipple acquiring additional bulk 
even before lactation commences, while nothing of the kind has been noticed 
in the Ornithorliynchus. He considers them, therefore, as being analogous 
rather to those glands for the secretion of a lubricating fluid, that are disposed 
along the flanks of the aquatic reptiles and fishes; or to the odoriferous 
follicles of quadrupeds, and especially to those which are found on the sides 
of the abdomen in shrews. To these objections Professor Meckel has re- 
* Ornithorhynchi paradoxi Anatome, fol. p. 58. 
t Annales des Sciences NatureUes, tom. ix. p. 457. 
