. Elements of comparative anatomy. Anatomy, Comparative. GENERATIVE ORGANS OF VERTEBRATA. 621 in which, and the extent to which, the chorion is connected with the raucous membrane of the uterus, and according to the modifications undergone by the latter organ. The copulatory organs form another series of parts formed by the differentiation of the wall of the cloaca. In the Selachii, indeed, organs which did not belong to the generative apparatus—• parts of the hinder appendages—are used as organs of copulation and modified accordingly, but new organs begin to be differentiated, which in
. Elements of comparative anatomy. Anatomy, Comparative. GENERATIVE ORGANS OF VERTEBRATA. 621 in which, and the extent to which, the chorion is connected with the raucous membrane of the uterus, and according to the modifications undergone by the latter organ. The copulatory organs form another series of parts formed by the differentiation of the wall of the cloaca. In the Selachii, indeed, organs which did not belong to the generative apparatus—• parts of the hinder appendages—are used as organs of copulation and modified accordingly, but new organs begin to be differentiated, which in the Amphibia are faintly indicated by the presence of a papilla which projects into the cloaca. These belong to one of two typical forms ; in one the organs are connected with the posterior, and in the other with the anterior wall of the cloaca. One of them is dominant in the Saurii and Ophidii. The copu- latory organs first appear as external appendages, placed just behind the cloaca ; later on these are invaginated in a tubular fashion (Fig. 355, p), and are only protruded during copulation. When protruded, each of these organs is continued into two more or less blunt ends, which vary in form. At the sides there is a groove, which is continued on from the cloaca, and which has a spiral course posteriorly, and is then directed towards the middle line; this serves to convey the sperm. The largest of the muscles supplied to it are the retractors, which are inserted into the blind end of the tubes. Glands open near the root of the tubes ( Penial tubes, ono of which is laid open Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Gegenbaur, C. (Carl), 1826-1903; Bell, F. J. (Francis Jeffrey), 1855-1924; Lankester, E. Ray (Edwin Ray), Sir, 1847-1929. London, Macmillan and Co.
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectanatomycomparative
