660 ANATOMY OF VERTEBRATES. 



vena dorsalis, and more deeply excavated below for the corpus 

 spongiosum urethras. 1 



^ § 375. In Sirenia. — These mutilate Mammals are also ( testi- 

 conda,' but differ from the Cetacea in having vesicular glands, a 

 penis with a ' septum corporis cavernosi,' and provided with a 

 pair of w levatores,' which unite to form a tendon upon the 

 ( dorsum.' In the Dugong (Halicore), the glans consists of two 

 semilunar side-lobes, including the conical process, on the apex 

 of which the urethra opens. In a half-grown male the vesicular 

 glands were four inches long and two inches across the fundus, 

 where their glandular parietes were thickest ; the internal sur- 

 face was reticulate. The vasa deferentia were irregularly con- 

 voluted : they communicated with the duct of the vesicular 

 gland, the common opening being into the dilated beginning of 

 the urethra, which describes a curve below the vesical orifice : 

 according to Louckart, it receives the opening of a bottle-shaped 

 protometra, about an inch in length. 2 



~? § 376. In Proboscidia. — The testes retain in the Elephant the 

 situation in which they were developed, viz. below or beyond 

 the kidneys. Their ducts have the same minor degree of density 

 as in Sirenia and other ' testiconda ;' they describe a tortuous 

 course to between the urinary bladder and vesicular gland, where 

 they terminate on a papillary eminence at the fundus of a true 

 seminal bladder, of a pyriform shape, with thin walls and a 

 smooth internal surface. These terminal reservoirs are in contact 

 and adherent : .they open into the beginning of the urethra 

 distinctly from the orifices of the vesicular glands. These are 

 elongated and rather contracted toward the closed end, which is 

 divided by a constriction or septum from the general cavity, with 

 which it communicates by a small canal. The glandular parietes 

 are thickest at the closed end, and the inner surface is broken 

 by decussating columnar processes projecting into the cavity ; 

 their interspaces extend in many parts, like sinuses, deep into 

 the substance of the vesicular walls : towards the urethra these 

 walls become smoother. Each vesicle has a special muscular 

 investment, for expulsion of its secretion into the urethra. The 

 prostatic glands are two on each side, external to the vesicular 

 ones, and of much smaller size : they are also provided with a 

 partial muscular covering. A caecal rudiment of the protometra 

 extends from the base of the verumontanal cul-de-sac. The 

 corpora cavernosa penis are divided by a thick sclerous vertical 

 partition, and in transverse section present a reniform figure, with 

 1 xii. vol. iv. p. 87, No. 2527. 2 ccxxxix". p. 1429. 



