592 CLASS XVII. 



vas deferens is the continuation. Tlie two deferent vessels open 

 above the root of the penis into the urethra ahnost always hy two 

 distinct apertures. In the Monotremes, the penis, according to the 

 investigations of Home, Meckel, and more recently of Duvehnoy, 

 is also perforated; but this canal, since the urine is poured into the 

 cloaca, is not properly an urethra, but merely the seminal duct, 

 and has in consequence received the name of urethra seminalis^ . 

 In most mammals the so-named vesiculce semmales are met with ; 

 they are formed by eversions of the deferent vessels, and also 

 contain seminal fluid in some mammals; they are, however, at the 

 same time principally secreting organs and not mere reservoirs for 

 the secreted sjjerma'^. Their development and function are very 

 various ; they are particularly large and composite in the insecti- 

 vorous /eros^. In most mammals there is one or more prostatic 

 glands, which are placed around the commencement of the m-ethra, 

 and mingle their fluid with that of the deferent vessels. In many 

 mammals Coivpers (/lands also are present, which lie below the 

 prostate on the bulb of the urethra ; tlieir tissue consists of vesicles 

 connected in clusters, and, constantly surrounded by muscles, they 

 sometimes have also a proper investment of muscular tissue with 

 striped primitive bundles. These glands are wanting in the dog. 

 A blind sac, already known to Morgagni, which in man opens 

 into the urethra between the apertures of the vasa deferentia, has 

 been observed in later times in many mammals, and from the 

 investigations of Webee and Huschke has assumed an important 

 morphological character as the remains of an uterus mascidinus 

 which is present in the foetus*. The ^ems is always undivided, 



^ Memoires de la Socicie d'Hist. nat. de Strasbourg, Tom. i. Livr. 2, 1833, pp. i — 10, 

 PI. II. Compare Owen in Todd's Cyclop, iii. p. 392. 



2 J. Hunter Observations on certain parts of the animal (Economy, London, 1837, 

 8vo (ed. E. Owen), pp. 20^33 ; — S. E. Pittaed Vesiculce seminales in Todd's Cyclop. 

 IV. pp. 1429— 1436. 



3 See for example the figures given by many writers of the male organs of propa- 

 gation of the hedgehog, as : Cakus TctS. Anat. comp. ill. Fasc. v. Tab. 9, fig. 5 ; Cata- 

 logue of the covip. Anat. in the Museum of the Coll. of Surg. iv. PI. 54, 55 ; Trevikanus 

 Beobacht. aus der Zoot. u. Physiol. 1839, Tab. 17, 18; those of the mole by Mueller 

 De Glandular, secern, struct, penit. Tab. iii. fig. 3, &c. 



* See E. H. Weber in the Berlcht der Versamml. der Naturforscher zu Braun- 

 schweig, 1842, s. 64; Huschke in his edition of S. T. Scemmerring's Lehre von den 

 Eingeweide, Leipzig, 1844; J. Van Deen hi Nicmo Archicf voor hinnen-cn buitenl. 



