PROSTATE GLAND. 



161 



In the agouti, the prostates are composed of 

 a trunk, divided into branches and ramusculi, 

 terminating in vesicular extremities. 



In the guinea-pig, the situation of the pros- 

 tate is occupied by a number of tubes folded 

 upon themselves, and connected together by 

 loose cellular membrane. 



The elephant has four prostate glands, two 

 on each side, external to the vesicula? semi- 

 nales, and near their base ; they are of un- 

 equal size, and very small in proportion to the 

 size of the other glands connected with the 

 generative function. They are muscular ex- 

 ternally, and are indistinctly lobulated. They 

 form a good illustration of the cellular type of 

 prostates, each consisting of a principal ca- 

 vity, into which smaller cavities open. The 

 smaller cells represent so many cul-de-sacs of 

 various sizes, communicating with each other 

 and with the principal cavity ; the excretory 

 duct is of large size, and passes by the side of 

 that of the neighbouring gland, to open sepa- 

 rately in the urethra by the side of the veru 

 montanum. 



In the wild boar the prostate is divided into 

 lobes, is very compact in its structure, and 

 forms a considerable projection at the begin- 

 ning of the urethra. There is also found in 

 this animal a glandular mass, analogous to the 

 prostate, surrounding the muscular portion of 

 the urethra, thickest at the commencement 

 of this canal, and surrounded by muscular 

 fibres coming from the neck of the bladder. 



In sotipedes there are two prostates, situ- 

 ated by the side of the vesicula? ; the cavities 

 of these are large, and the parenchyma small 

 in quantity ; they are covered by muscular 

 fibres coming from the vesicula? and neck of 

 the bladder ; their excretory ducts terminate 

 by many orifices on either side of the ducts of 

 the vesicula?. 



The ruminants have also two prostates, 

 precisely similar to the preceding. They are 

 larger in the ram and bull, and are composed 

 of distinct lobes, each containing small cells, 

 which communicate with a large central ca- 

 vity ; this opens by a duct in a large lacuna of 

 the veru montanum, either internal to or be- 

 hind the vas deferens. In the stag, axis, and 

 buffalo they are smooth, and of a regularly 

 oval shape, and have a central cavity commu- 

 nicating by large openings with smaller cavi- 

 ties ; each has a single duct, which terminates 

 generally behind the corresponding vas de- 

 terens. The only difference in this class is in 

 regard to size ; for in the chamois each is as 

 large as a pullet's egg, and contains a propor- 

 tionably large cavity ; so that it has been 

 occasionally mistaken for a reservoir of semi- 

 nal fluid. In the seal, amongst the quadri- 

 remes, it resembles that of the otter. In 

 the cetacea there is a large glandular mass, 

 covering a large portion of the first part of the 

 urethra, especially at the upper part, covered 

 by a strong muscle. When a section is made, 

 it is found to consist of large cells ; its ducts 

 open separately by numerous orifices on the 

 urethra. 



VOL. IV. 



In the marsupial sub-class, as in the kanga- 

 roo, the prostate is found surrounding thecom- 

 mencement of the urethra, of large size, and 

 conical in shape, with base behind, apex in 

 front ; it is surrounded by a strong musculo- 

 membranous capsule. It exceeds in diameter 

 the contracted bladder, and is made up of 

 tubes ramifying perpendicularly to the urethra, 

 which subdividing terminate in minute cceca 

 upon the surface of the gland. It presents a 

 similar arrangement in the opossum ; whilst 

 in the wombat its existence is doubtful. 



Carus has described in birds a dilatation of 

 the vas deferens, a rudimentary vesicula semi- 

 nalis, and a small gland like a prostate near 

 the termination of the vas deferens. This is not 

 admitted by Owen. In the ornitlwrynchus 

 paradoxiis we find two round glandular bodies 

 representing Cowper's glands, but which may 

 be fairly regarded as a rudimentary prostate. 



Amongst amphibious reptiles, glands ana- 

 logous to the prostate, or Cowper's glands, 

 are found. In the salamander they are com- 

 posed of two lobes ; one placed horizontally, 

 and the other vertically ; the former, in the 

 common salamander is heart-shaped, with the 

 point behind ; and in its centre a fissure is 

 seen. The vertical lobe is raised obliquely 

 towards the dorsal aspect, so that an interval 

 is left between them for the passage of the 

 kidneys ; a muscle separates the two. 



In the black salamander, each gland is com- 

 posed of two lobes. In the Tritons the part 

 of the prostate which corresponds with the 

 inferior lobe is still more complicated; it forms 

 the wall of the vestibulum in the shape of a 

 cup. Besides this, there are two pelvic pros- 

 tates corresponding to the vertical lobe of the 

 vestibular prostate of the salamander ; they 

 occupy the dorsal aspect of the vestibule and 

 the pelvis, and each is subdivided into two 

 lobes. Their excretory ducts open in the 

 mesian line of the furthest point of the vesti- 

 bule. The Tritons have a third prostate occu- 

 pying a large portion of the abdominal muscles 

 under the peritoneum. In structure they re- 

 semble those of the hedgehog. (Cuvier.) 



BIBLIOGRAPHY. NATURAL STRUCTURE. See 

 anatomical works in general. Miiller, De penitiori 

 Glandularum Structura, 1830. 



PHYSIOLOGY. For the opinions of the ancients 

 on this subject see Hatter's Elementa Physiologias, 

 vol. 7., and the opinions of modern physiologists are 

 set forth in the works of physiology generally. Cow- 

 per, Glandularum quarundam uuper detectarum, 

 1702. 



COMPARATIVE ANATOMY. See vol. 8. of Cuvier's 

 Lecons d'Anatomie Compare'e. Lectures on Compa- 

 rative Anatomy, by Dr. Grant, in the Lancet, and 

 Lectures on Comparative Anatomy by Rymer Jones. 

 See also various articles by Professor Oicen on Com- 

 parative Anatomy in this Cyclopaedia, Owen's 

 Lectures on the Comparative Anatomy of the 

 Invertebrata, 18-13. Wagner's Elements of the Com- 

 parative Anatomy of the Vertebrate Animals, trans- 

 lated by Tulk, 1845. 



DEVELOPMENT. Acherman, Infantis Anclrogyni 

 Historica, Jena, 1805. Mechel, Abhandlungen 

 aus der menschl. und vergl. Anatomie, 180G. Tiede- 

 man, Der Kopflosen Missgeburten, 1819. Miiller, 

 Bildungeschichte der Genitalien, 1830, and Archiv. 



M 



