General outline of the organization of the animal kingdom : and manual of comparative anatomy / by Thomas Rymer Jones, F.R.S.

  • Jones, Thomas Rymer, 1810-1880.
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: General outline of the organization of the animal kingdom : and manual of comparative anatomy / by Thomas Rymer Jones, F.R.S. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    Fig. 560. query tliat has not been satisfactorily answered ; and its generative ap- paratus is so nearly related to that of an oviparous animal that even anatomy throws but little light upon the subject. (2425.) Both in the male and female there is, in fact, but one vent that leads to a cloaca! chamber resembling that of a bird; and the entire organization of the sexual organs is rather that of an egg-laying than of a vi- viparous creature, as will be evident from the following details respecting them.. (2426.) The penis of the male OrnitJio- rhynchus is perforated hy a urethral canal, through which the semen passes, but not the iirine; its extremity, moreover, is termi- nated by two tubercles, giving it almost a bifid appearance. This penis, when in a relaxed state, is lodged in a little pouch in the floor of the cloaca, from which it projects when erected. (2427.) The cloacal cavity, as in birds, gives passage to the fteces and to the urine. The testes (fig. 560, a) and the vasa de- ferentia (b) resemble those of an oviparous animal; but, on the other hand, there is a complete urinary bladder (c), and moreover a pair of auxiliary (Cowper's) glands {d d), organs never met with except in the Mam- miferous class. (2428.) The anatomy of the female or- gans is not less singxilar. The ovaria (fig. 562, a a) are large and racemose, like those of a bird ; while the two oviducts or uteri, (fig. 561, a a), as the reader may choose to call them, open into the cloaca by two j^ale generative organs of Ornitho- distinct orifices (c c) situated on each side '-^f^f paradoxus- a testes; 6, b, ^ vasa deferentia; c, bladder; d, d, Cow- of the urethra, derived from the bladder (6). per's glands. (2429.) It is to Professor Owen that science is indebted for all that is known relative to the anatomy of the female Ornithorhynchus when in a gravid state; and his researches upon this subject appear to establish the following interesting particu- lars : First, that the ovaria, notwithstanding their racemose appear- ance, exhibit all the essential characters of the Mammiferous type of structure ; and corpora lutea were found where the reproductive germs had escaped from them. Secondly, that the eggs contained in the uterine cavities (fig. 562, c, e) had no connexion whatever with the walls of the uterus. Thirdly, that each ovum exhibited the usual parts