666 



ANATOMY OF VERTEBRATES. 



also a pair of ' retractores ' arising from the os coccygis, fig. 522, 

 /;, q, passing on each side the sphincter ani, r, then converging to 

 run together along the urethral side of the penis, .<?, to the base of 

 the prepuce. In the castrate horse these usually degenerate into 

 elastic sclerous tissue. 



378. In Artiodactyla.- -The male organs of the Suidce are 

 chiefly remarkable for the enormous development of the Cow- 



523 



Protoinetra, &c. of the Ass. rcxxxiv". 



penan glands. The testes are perinaeal: the scrotum slightly 

 projects ; it is not pendulous. The vesicular glands are large, 

 tabulated, with parenchymatous walls, their ducts terminate dis- 

 tinctly from those of the testes. The prostates are small, near 

 the cervix of the vesiculas. The muscular part of the urethra 

 is of great length and the Cowperian glands are co-extended 

 therewith : each presents an elongate subtrihedral form, invested 

 by a muscular capsule ; the glandular parietes are very thick : 



