Illustrations of gross dissections of the penis and perineal muscles in a male mouse (A), Damaraland mole-rat (B), and silvery mole-rat (C).

<p>Dorsal is down. (A) In the mouse, the LA loops around the rectum and attaches to the base of the penis. Attachment sites of the LA are completely obscured by the bulbous BC, which encircles the ventral LA and also attaches to the penile bulb. A moderately sized IC is seen. (B) Damaraland mole-rats and (C) silvery mole-rats lack a prominent BC, leaving the ventral LA more exposed. Both Damaraland and silvery mole-rats possess large IC muscles and anal sphincters. Cowper's gland has been removed on the right side in (A) and (C). Cowper's gland was smaller and tucked under the LA in Damaraland mole-rats. Abbreviations: AS, anal sphincter; BC, bulbocavernosus; IC, ischiocavernosus; LA, levator ani. Scale bar = 500 µm.