103 



problem still remained, how a quadruped, with a beak like a duck, 

 could suck, or in any way obtain milk from a mammary organ with- 

 out a nipple. In 1834 Professor Owen received specimens of young, 

 and apparently newly-born, OrnithorJiyncJii, from Air. George Bennett 

 and Dr. Weatherhead : their form and anatomy are minutely de- 

 scribed in a paper in the Transactions of the Zoological Society. 

 The oral orifice was there shown to be exactly adapted to be applied 

 to the areola of the breast on which the lactiferous ducts terminate, 

 and to receive the milk that is injected into the mouth by a muscle 

 that surrounds the large mammary gland*. The remains of foetal 

 peculiarities in these young specimens confirmed the inference from 

 the structure of the ovum that the Ornithorhynchus was viviparous, 

 but implacental. 



Professor Owen's next step was to settle the questions undecided 

 on the generation of marsupial animals — the period of uterine gesta- 

 tion, the exact condition of the new-born young, the mode of its 

 passage to the external pouch, and the term of its suspension to the 

 pendulous nipple. On all these points science was, as yet, unin- 

 formed. The Kangaroo (Macropits major) had bred in captivity, in 

 both France and England. Professor Owen took advantage of the 

 opportunities which the menagerie of the Zoological Society afforded 

 to obtain exact data on the chief points which most needed eluci- 

 dation. You will find the account of his experiments in the paper 

 * On the Generation of the Marsupial Animals,' in the Transactions 

 of the Royal Society for 1834. The period of uterine gestation of 

 the Great Kangaroo is shown to be thirt}--eight days ; the new-born 

 animal is but one inch in length, naked, blind, with hind-legs and 

 tail shorter than the fore-legs. He ascertained that the mother 

 transferred her minute and delicate progeny from the vulva, to the 

 nipple concealed in the pouch, by means of her lips ; that the em- 

 bryo instinctively adheres to the nipple, and is suspended to it for 

 a period of six months. 



In the Philosophical Transactions for 1837 appeared a memoir 

 from Professor Owen's pen, describing certain peculiarities in the brain 

 of the Marsupialia, especially the absence of the corpus callosum. 

 The same condition he subsequently discovered in the Ornithorhyn- 

 chus and Echidna. This and other peculiarities of structure in the 

 sanguiferous, osseous and dental systems, led Professor Owen to sug- 

 gest a modification of the classification of the Mammalia, which 

 Cuvier had adopted in his last edition of the ' Regno Animal.' Deem- 

 ing modifications of brain of more importance than those of the 

 ungual phalanges, and connecting the higher development of the 

 commissural system of the brain with the longer sojourn of the foetus 

 in the womb and its more intimate union therewith, Professor Owen, 

 in his paper ' On the Classification of the Marsupialia,' in the Trans- 

 actions of the Zoological Society for 1839, groups together all the 

 Mammalia which have a placenta under any form, and which have 



* An analogous arrangement had been previously shown to exist in the Kan- 

 garoo, by the late Mr. John Morgan. 



