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reception of the Monotr etna tons Quadrupeds of New Holland, and of 

 separating them altogether from the Mammalia, arose chiefly from 

 the supposition of the total absence of a mammary apparatus in them. 

 This circumstance was at the same time regarded as a strong proof 

 of an essential difference in their mode of producing the young : and 

 it was inferred that the latter, in the absence of the lacteal nourish- 

 ment, must have derived the materials necessary for their develop- 

 ment from some store of nutriment analogous to the yelk of the em- 

 bryo in the oviparous and ovoviviparous tribes. 



" But the converse of this proposition, that a mammiferous animal 

 must necessarily be viviparous, by no means follows. The develop- 

 ment of an animal may be carried on to a certain degree either in 

 the oviparous or ovoviviparous mode of generation, and yet after in- 

 cubation or birth, additional store of nutriment may be required from 

 the parent in order that the processes of organization may be 

 completed to the extent neeessary to enable the young animal to 

 gain a subsistence by its own exertions. Indeed, when we consi- 

 der how long, in many of the orders of Birds, the unfledged young 

 are totally dependent on their parent for their nutriment j that this nu- 

 triment, though in general foreign matter, collected with much indus- 

 try and frequently at great risk, yet is sometimes, as in the Pigeon, a 

 secretion from the parent's body j and when we further reflect that 

 generation in the Marsupiata is essentially of the ovoviviparous kind, 

 — we shall have no difficulty in reconciling ourselves to the considera- 

 tion of the Monotremata as oviparous or ovoviviparous, and at the 

 same time as mammiferous, animals. 



" With respect to the Ornithorhynchus, it seems incontrovertible 

 that the apparatus discovered by Meckel is truly mammary, and exe- 

 cutes the important function of providing the lacteal nutriment for 

 the young. Nevertheless, this discovery leaves us just as much in 

 the dark as we were before respecting its mode of generation, and 

 equally dependent on the exertions of those naturalists who may 

 have the good fortune of observing facts in the living animal respect- 

 ing this most interesting and important subject. It is obvious also, 

 that the discovery of the mammary glands in the other monotrema- 

 tous genus, although highly confirmatory of their accordance with 

 the rest of the Mammalia in the characteristic function of lactation, 

 yet by no means renders less necessary an unremitting attention to 

 every habit of the living animal which may elucidate the processes of 

 generation. 



" In the meanwhile, however, it affords me much pleasure to be 

 able to lay before the Committee preparations of the mammary glands 

 from the Echidna Hystrix, which, as the following description will 

 show, afford an additional instance of the close affinity subsisting be- 

 tween it and Ornithorhynchus, notwithstanding the great dissimila- 

 rity existing between them in external form and in the nature of 

 their integuments. These glands were discovered in a female spe- 

 cimen not quite arrived at maturity, and which therefore in all pro- 

 bability had never been impregnated. They are consequently very 

 small, as compared with those which have been observed in Orni- 

 thorhynchusj but are precisely analogous in number, form, composi- 



