OF MONOTREMATA AND M ARSUPI ALIA. 
4G7 
animals among the Edentata, but used Geoffroy’s term, Monotremata. Oken 
suggested that the mammary glands might occupy some unusual position, and so have 
escaped notice. In 1817, also, Sir John Jamison (38), writing from Australia to the 
Secretary of the Linnean Society, described the spur of the male, and stated that the 
female was oviparous. Sir Eyerard Home (37), in 1819, discovered that the left 
ovary alone was functional, and that in the ovary the egg-follicle contained a large 
quantity of yolk, like a Bird’s. 
In 1820 Mr. Patrick Hill, Surgeon, Pv.N. (34), made some observations which 
caused him to write to the Linnean Society; the letter was dated January 3, 1821, 
but was not read until December 1 8. Mr. Hill describes how he found an “ egg in 
the left ovarium,” “ of the size of a pea, and of a yellow colour.” This specimen was 
sent to England by a Mr. Scott, examined by Sir Eyerard Home, and afterwards 
presented to the University of Oxford. This ovarian follicle of Hill’s gave rise to 
considerable misunderstanding; thus Fleming, in his ‘ Philosophy of Zoology,’ 1822, 
p. 215, stated that Ornithorhynchus eggs had been transmitted to London. Recently, 
Beddard (2) has quoted Fleming, but omitted to point out that the latter knew 
that the egg referred to had not been laid, as Fleming added, “ It would be 
interesting to know the manner of incubation, and whether oviparous or ovo- 
viviparous.” In the ‘Isis’ for 1823, col. 1425, Oken, after printing Geoffroy’s 
remarks, and Hilt/s letter on which they were based, disposes of the “ celebrated 
history of the Ornithorhynchus egg” by pointing out the Mammalian characters of 
Hill’s Graafian follicle. Oken concludes by saying that the whole story arose from 
the mammary glands not having been observed. 
In 1823, however, Meckel (40) discovered mammary glands, and his great work 
(41) was published in 182G. Meckel, while rejecting both Hill’s evidence and 
Oken’s arguments, pointed out that there was little difference between viviparity and 
oviparity, since Birds had been artificially made to incubate their eggs in the oviduct. 
Geoffroy had by this time become convinced that the animals were oviparous, and 
he soon denied (22) that Meckel’s glands were mammary. In 1829 Geoffroy 
obtained, through Professor Grant, the egg-shells which had been sent from Australia 
as veritable Ornithorhynchus eggs. Geoffroy (23) figured the egg, but soon after¬ 
wards discovered that it was too large for Ornithorhynchus. In 1827 Geoffroy (22) 
had stated that the diameter of the pelvis was not more than 5 lines. The reputed 
egg measured if inch X finch. Geoffroy’s first hypothesis, 1827 (22), was that 
the egg was formed in the cloaca, but so rapidly as not to cause a serious obstruction ! 
His second, 1833 (27), was that the egg remained in the oviduct until hatching, 
because it could not pass through the small pelvis. 
In 1832 the first direct evidence bearing on the question was published in the 
‘ Proceedings of the Committee of Science and Correspondence of the Zoological 
Society of London.’ 
Lieut, the Hon. Lauderdale Maule (39) wrote to his friend Dr. Weatherhead 
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