File:The cyclopædia of anatomy and physiology (1836) (20812175192).jpg

Title: The cyclopædia of anatomy and physiology
Identifier: cyclopdiaofana01todd (find matches)
Year: 1836 (1830s)
Authors: Todd, Robert Bentley, 1809-1860
Subjects: Anatomy; Physiology; Zoology
Publisher: London, Sherwood, Gilbert, and Piper
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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AVES. 355 everted, and the semen brought into contact with the similarly everted orifice of the oviduct in the female, along which the fecundating fluid is impelled by the vibrations oi' the cilia or the mucous surface through all the windings of that tube to its ultimate destination. In the Natalores which copulate in water there is an obvious necessity for a more effici- ent coitus than a simple contact of everted cloacse, and consequently in these birds, as the Swan, Gander, Drake, &c. a long, single penis is developed. Fig. 184.
Text Appearing After Image:
Penis of a Drake. This body arises from the front part of the outer compartment of the cloaca (a, a, Jig. 184) immediately below the urethro-sexual cavity; it is in the unexcited state coiled up like a screw from the elasticity of the internal liga- mentous structure. The external coat is a pro- duction of the membrane lining the outer cavity, and gives ofi a number oi'small pointed processes, which in the Gander are arranged in transverse rows on either side the urethral groove, and near the extremity oi' the penis are inclined backwards. The body (b b, Jig. 184, where it has been cut open) is composed of a white elastic ligamentous substance, and a vascular pulp, but without any of the cellular structure which characterizes a corpus caver- nosum. A groove (dd), commencing widely at the base is continued along the side of the ligamentous substance, and follows all the spiral turns of the penis to its extremity. The vasa deferentia terminate in papilloe at the base of this groove, along which the semen is transmitted to the vagina of the female.* The penis of the Ostrich is also single, and the urethra is represented by a dorsal groove; it is disposed in a slight spiral bend when in a retracted state. It arises by two strong liga- mentous crura from the cartilage uniting the bones of the pubis, and descends into the external or preputial compartment of the cloaca. There are four muscles to the penis of the Ostrich : two arise from the inside of the os sacrum, and descending along the preputial cavity, are inserted into the base of the penis: two other muscles pass from the internal part of the iliac bones, to be attached to the sides of the penis. The Guan (Penelope cristata) presents a singular exception to the other Rasorial Birds in having a single linguiform pointed penis developed, the sides of which are provided with retroverted papilla?, as in the Anserine Birds. In the Gallinule, which seeks its food in water, there is no penis ; it, therefore, most probably copulates on land. The tumid margin of the preputial cavity of the penis is well provided with large mu- cous follicles which secrete a sebaceous lubri- cating substance; of these there are twelve in the Gander, arranged six on each side. These may be regarded as analogous to the glandules odoriferte; but there is no vestige either of prostatic or other urethral glands. Female organs of generation.—An ovarium or productive organ, (a, b, c, d, Jig. 185,) with an oviduct or efferent tube (e, f, g, k, I,) are present in all birds, and a clitoris or organ of * We cannot account for the error into which Sir Everard Home has fallen, in describing the urethra of the drake as a complete canal, and the penis as being enclosed within a prepuce. (Phil. Trans. 1802, pp. 361,363.) Repeated dissections of different species of Anas, Cuv. have satisfied us of the accuracy of Mr. Hunter's statement, that " birds have no urethra, some having merely a groove, as the Drake and Gander, and many being even without a groove, as the common Fowl." Animal (Economy, p. 40. The letter c, in Sir Everard Home's figure, (fig. 184,) points to the orifices of mucous glands or cut vessels, and not to the papillae, on which the vasa deferentia termi- nate. 2 A 2

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