the male organ of copulation and of urinary excretion, comprising a root, body, and extremity, or glans penis. The root is attached to the descending portions of the pubic bone by the crura, the latter being the extremities of the corpora cavernosa, and beneath them the corpus spongiosum, through which the urethra passes. The glans is covered with mucous membrane and ensheathed by the prepuce, or foreskin. The penis is homologous with the clitoris in the female.