=M. caudoanalis= (S.-D.) (Fig. 113, _f_; Fig. 114, _g_).--A slender, flat bundle of fibres having origin on the middle line of the ventral surface of the second and third caudal vertebræ. It passes caudoventrad, lying between the levator ani and the caudorectal (Fig. 113, _e_; Fig. 114, _j_), and unites with the ventral portion of the sphincter ani internus (Fig. 113, _h_). _Action._--Draws the anus craniodorsad. [Illustration: FIG. 113.--MUSCLES OF THE ANUS, UROGENITAL ORGANS, AND TAIL IN THE MALE (SLIGHTLY SCHEMATIC). One side of the pelvis has been removed, _a_, _a′_, M. extensor caudæ lateralis; _b_, M. abductor caudæ externus; _c_, _c′_, M. flexor caudæ longus; _d_, M. flexor caudæ brevis; _e_, M. caudorectalis; _f_, M. caudoanalis; _g_, M. caudocavernosus; _h_, M. sphincter ani internus; _i_, M. sphincter ani externus; _j_, M. levator scroti; _k_, M. rectocavernosus; _l_, M. bulbocavernosus; _m_, M. ischiocavernosus (cut); _n_, M. compressor urethræ membranaceæ. 1, tail; 2, rectum; 3, bulbourethral or Cowper’s gland; 4, prostate gland; 5, symphysis pubis; 6, penis; 7, glans penis; 8, testis; 9, spermatic cord.] =M. caudorectalis= (Fig. 113, _e_; Fig. 114, _j_). _Origin_ from the ventral surface of the sixth and seventh caudal vertebræ. A small, at first unpaired band two or three millimeters wide is formed, which passes cranioventrad, soon dividing into two lateral halves. These spread out over the sides of the rectum, forming a broad sheet of fibres which pass into the walls of the rectum, among the transverse fibres of the latter. This muscle is covered by the caudoanalis (Fig. 113, _f_), caudocavernosus (_g_) (or caudovaginalis, Fig. 114, _h_), iliocaudalis, and levator ani. _b. Muscles Peculiar to the Male_ (Fig. 113).--=M. levator scroti= (_j_).--This is a band of fibres which passes ventrad in the median line from the sphincter ani externus (_i_) onto the scrotum. Here it spreads out beneath the skin, forming especially a well-marked bundle in the median furrow between the two testes. =M. rectocavernosus=, or =retractor penis= (_k_).--A small bundle of fibres which arises in two parts from the ventral surface of the sphincter ani internus (_h_). The two parts unite into a single bundle which passes caudad on the middle line of the ventral surface of the penis; it is inserted into the corpus cavernosum just proximad of the glans. The muscle is covered only by integument, and overlies the ischiocavernosus (_m_). =M. caudocavernosus= (S.-D.) (_g_).--A slender bundle just craniad of the caudoanalis (_f_). _Origin_ on the median ventral line of the first two caudal vertebræ. The muscle passes caudoventrad, lying between the levator ani and the caudorectal (_e_). It divides into two bands, one of which is inserted into the base of the corpus cavernosum, while the other extends farther caudad and is inserted at the distal extremity of the corpus cavernosum. _Action._--Flexes the penis (bends it backward).