. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 399 tical membrane it is probable that this does not become organized into a placenta, and that the Monotrewuta like the Marsupiata are essentially ovoviviparous. Since, however, the female Or- nithorhynchus has no tegumentary pouch to pro- tect a prematurely born offspring, it must be pre- sumed that the foetus acquires greater propor- tional bulk* and more mature strength by a longer continuance within the uterus. In this respecting the young Ornithorhynchus, pro- bably not long excluded from the foetal e
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 399 tical membrane it is probable that this does not become organized into a placenta, and that the Monotrewuta like the Marsupiata are essentially ovoviviparous. Since, however, the female Or- nithorhynchus has no tegumentary pouch to pro- tect a prematurely born offspring, it must be pre- sumed that the foetus acquires greater propor- tional bulk* and more mature strength by a longer continuance within the uterus. In this respecting the young Ornithorhynchus, pro- bably not long excluded from the foetal enve- lopes, by an examination of two specimens, obtained by Lieut, the Hon. Lauderdale Maule, from two different nests, discovered by him in the banks of the Fish River, Australia, and presented by Dr. Weatherhead to the Zoolo- gical Society of London. Subjoined is an outline of the smaller of case it may be doubled whether the vilellme these specimens of the natural size (jig. ). vesicle will suffice for nourishment and respi- ration through the whole period of develop- ment, and the allantois and umbilical vessels will probably be more expanded for that pur- pose. The means of prosecuting this inquiry are the more likely to be afforded, since, through the exertions of Mr. Bennett, the period when the pregnant female may be procured is now ascertained. Had not a specimen, supposed to be in this condition, which my friend had obtained alive, unfortunately escaped from its confinement, he would, there is little doubt, have ascertained the true nature of the gene- rative product, and the probable duration of gestation. With reference to the latter point, Mr. Ben- nett observes, that two months after the cap- ture of the female specimen with the smallest ova, viz. on the 8th of December, 1832, he succeeded in laying open one of the burrows of the Ornithorhynchi on the banks of the Mur- rumbidgee River, in which three living young ones were found: they were naked, and me
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