20 
MON OTIiE M AT A. 
classes; and, on the other hand, as birds have been known to 
hatch the eggs within their body, and to give birth to a living 
chick, ho thought it highly probable that the generation of 
the Omithorhynchus, approaching still more nearly to birds 
and reptiles than the Marsupialia, might be oviparous. 
Geoffrey St.-Hilaire, Oken, De Blainville, and Prof. Owen, 
took active parts in the discussion of this question: the 
former supposing the mammary glands were wanting, 
removed the Omithorhynchus from the class Mammalia, 
and arranged it, together with the Echidna, in a separate 
class, to which he affixed the name Monotrema 1 ; and, 
subsequently, when Meckel had shown the existence of 
the glands in question, Geolfroy St.-Hilaire still firmly 
maintained liis opinion 2 . These glands he conceived to be 
analogous to those situated along the flanks of the salamanders, 
or to the odoriferous glands observed on the sides of the 
abdomen in shrews. At an early period, De Blainville 
rightly conjectured that mammary glands would be found in 
the Omithorhynchus, and that the animid would prove to be 
allied to the Marstt-piaia?. 
In two Memoirs published in the Philosophical Transac¬ 
tions 4 , and a third paper published in the Transactions of the 
Anatomic Phitosophique , tome i. 1818. Sir Evernrd Home, it mu«t be 
observed, had previously pointed out the close relationship of affinity which 
existed between the Omithorhynchus and Echidna, and called particular atten- 
tion to various peculiarities in the sexual organs of these animals.—See his 
paper, On the Anatomy of the Omithorhynchus, in the Philosophical Trans¬ 
actions for lb02, vol. 92, p. G7 ; and on the Ornithorhvnchns hvstrix, loc. cit. 
p. 348. 
- See Annates ties Sciences Nature!lex, 182G, p. 457. 
3 An excellent summnry of the interesting controversy relating to the mam- 
marj glands, &c., of which nn outline only is here given, will be found in Ihc 
article Omithorhynchus, in the Penny Cyclopicdia, from the pen of Mr. 
Brodcrip. 
On the Mammnry Glands of the Omithorhynchus parwloxvs, Phil. Trans. 
1H32, part 2; and ou the Ova of the Omithorhynchus paradoxus, Phil. 
Trans. 1831, part 2. 
