572 



GENITAL ORGANS OF THE STALLION 



Structvire of the Testicle and Epididymis. — The greater part of the surface 

 of the testicle is covered by a serous membrane, the tunica vaginalis propria, which 

 is the visceral laj^er of the serous envelop of the cord and testicle; this is reflected 

 from the attached border of the gland, leaving an uncovered area at which the 

 vessels and nerves in the spermatic cord reach the testicle.^ Beneath this serous 

 covering is the tunica albuginea, a strong capsule composed of dense white fibrous 

 tissue and unstriped muscle-fibers. When the tunic is cut, the gland substance, 

 which is soft and reddish gray in color, protrudes. From the attached border and 

 from the deep face of the tunica albuginea trabeculse and septa of connective tissue 



^}i?^^hi. 



Fig. 513. — Inguinal Region of Stallion, with Testicles Exposed. 

 a, a', Testicles; b, scrotum, opened and reflected; c, tunica vaginalis communis, opened and reflected; d, reflection 

 of tunica vaginalis enclosing scrotal ligament; e, tunica vaginalis propria (mesorchium) ; /, ductus deferens; g, g', tail 

 of epididymis; h, body of same; i, head of same; k, sinus epididymidis; /, spermatic vessels showing through tunica 

 vaginahs propria; m, spermatic artery; n, prepuce; n' , raph6; o, preputial orifice. (After Ellenberger-Baum, Top. 

 Anat. d. Pferdes.) 



and unstriped muscle (Septula testis) pass into the gland and subdivide the 

 parenchyma into lobules (Lobuli testis). The larger trabeculse radiate from the 

 attached border into the central part of the gland. 



A distinct mediastinum testis, such as is present in man and many animals, does not exist in 

 the horse. The trabeculiE and interlobular septa form a network which shows no special conden- 

 sation in any part of the gland. In correlation with this is the absence of a rete testis, formed by 

 the anastomosis of the seminiferous tubules in the mediastinum. 



The spaces imperfectly marked off by the septa contain the parenchyma 

 testis, which consists of seminiferous tubules (Tubuli seminiferi), supported 



1 In the normal state the surface of the testicle is quite smooth on account of the serous 

 covering. Frequently, and especially in old subjects, local inflammation has produced roughen- 

 ing of the surface and thread-like proUferations. 



