594 



MALE GENITAL ORGANS OF THE DOG 



tissue (pars disseminata) are also found in the wall of the urethra for a short distance 

 further back. The gland is subject to much variation in size, and is often enlarged, 

 especially in old subjects. 



The position of the prostate varies. When the bladder is empty and contracted, the gland 

 is entirely in the pelvic cavity and may be an inch or more behind the anterior border of the 

 pubis, ^^'hen the bladder is full, the prostate is often largely or entirely prepubic. 



The uterus masculinus is a small compressed saccule in the colliculus seminalis- 



The bulbo-urethral glands are absent.^ 



The penis presents several special features. In its posterior part there are two 

 distinct corpora cavernosa, separated by a median septum penis. In its anterior 

 part there is a bone, the os penis, which in large dogs reaches a length of four inches 

 (ca. 10 cm.) or more. It is regarded as a part of the corpus cavernosum which has 



Fig. 528. — Exteenal Genital Organs of Male Dog; Ventro- 

 lateral View of Preparation. 

 1, Scrotum; /', tunica vaginalis; 3, epididymis; 3, vascular 

 part of spermatic cord; 4, ductus deferens; 6, prepuce; 5,^pars longa 

 glandis; 6', corpus cavernosum penis; 7, bulbus glandis; 7', con- 

 tour of bulbus in erection; 5, ischio-cavernosus muscle; a, acetab- 

 ulum; h, obturator foramen. (After Ellenberger, in Leisering's 

 Atlas.) 



Fig. 529. — Internal Genital Organs of 

 Male Dog; Dorsal View. 

 1, Urinary bladder; 2, ureter; S, ductus 

 deferens; 4-i prostate; 5, urethral muscle; 6, 

 bulb of urethra; a, abdominal w^all; 6, ilium; 

 c, ischium. (After Ellenberger, in Leisering's 

 Atlas.) 



ossified. Ventrally it is grooved for the urethra; dorsally it is convex, and an- 

 teriorly it becomes smaller and has a curved fibrous prolongation. ^ The glans 

 penis is very long, extending over the entire length of the os penis; its anterior 

 part, the pars longa glandis, is cylindrical, with a pointed free end; behind this 

 there is a rounded enlargement, the bulbus glandis. Both are composed of erectile 

 tissue. The two dorsal veins arise from the bulbus glandis, pass backward on the 

 dorsum penis, and unite at the ischial arch. A small muscle (M. compressor venae 

 dorsalis penis) arises from the tuber ischii on either side; the two converge on the 

 dorsum penis near the bulbus glandis. They compress the dorsal veins, and may 

 also tend to elevate the penis and thus assist in copulation. The other muscles 

 offer no features worthy of special description. 



1 They are present in the cat, and are the size of a pea. 



^In the young subject it has a prolongation composed of hyaline cartilage, which becomes 

 fibrous later. 



