520 
MR. OWEN ON THE MAMMARY GLANDS 
posed by Professor Geoffroy, but admitted it in the Regne Animal, as indi¬ 
cative of a tribe or family only, in his order Edentata. 
Oken and De Blainville more decidedly opposed the opinion of Geoffroy. 
The former naturalist even went so far as to hazard a conjecture respecting 
the mammary glands, and suspects that they will be found in the Cloaca, 
(Zoologie, tom. ii. p. 957); and M. De Blainville, in a dissertation on the 
place which the Ornitliorhynchus and Echidna ought to hold in the natural 
series, after adducing the numerous instances in which the structure of the 
Monotremata agrees with that of the Mammalia, also expresses his belief that 
the mammary organs will ultimately be detected, and is of opinion that the 
animals themselves are most closely allied to the Marsupial order. Lastly, 
Professor Meckel, of Halle, announced in Froriep’s Notizen, (Band vi. 
p. 144. 1824.) and subsequently in his excellent monograph on Ornithorhyn- 
clius paradoxus, (folio, Lipsise, 1826,) the existence of mammary glands largely 
developed in the female of that species *. In the latter work he accurately 
describes their situation, magnitude, form, and lobular composition. The 
tissue of the lobules he regards as consisting of closely aggregated tubes. 
Being unable to inject the gland, he is uncertain as to the precise mode in 
which the ducts terminate; but describes some small eminences, situated in 
the middle of the areola, as being undoubtedly orifices of the ducts. 
From this most important example of the affinity of the Ornitliorhynchus to 
the ordinary Mammalia, Professor Meckel is, however, far from drawing 
conclusions as to the identity of their mode of generation. For observing, 
“ that the difference between the bringing forth of living young and of eggs is 
really very small, and by no means of an essential nature,—that birds have 
accidentally hatched the egg within the abdomen, and so produced a living 
foetus,—an occurrence which has also been induced by direct experiment T,— 
and that, lastly, the generation of the marsupial animals is very similar to the 
oviparous mode,” he deems it “ very probable that, as the Ornitliorhynchus 
* This description has been translated into the French language and published by De Blainville 
in the Bulletin de la Societe Philomathique, tom. is. p. 138 : and into our own language by the Editor 
of the second edition of Lawbence’s translation of Blumenbach’s Comparative Anatomy. 
t Probably in allusion to the Experiences sur la Generation des Animaux Ovipares, par M. Rossi, 
M£m. de l’Acad. de Turin, 1779, p. 266. 
