Table 2. Anatomical features defining male and female external genitalia of mice and broad-footed moles.

Structure	Anatomical features
Penis	Contains erectile bodies Urethra completely surrounded by penile stroma Lacks hair Housed within the preputial space Is an “internal” organ May contain bone May have surface spines Rod-like morphology Circular/oval in transverse section
Male prepuce	Lacks erectile bodies Lacks a urethra Hair-bearing outer surface Defines the preputial space Inner surface lined by a glabrous epithelium Lacks bone Houses the penis Penile urethra opens into preputial space Projects as an elevation in the perineum
Female prepuce	Lacks erectile bodies Lacks a urethra Hair-bearing outer surface Defines the preputial space Inner surface lined by a glabrous epithelium Lacks bone Urethra opens into preputial space Projects as an elevation in the perineum
Clitoris	Is an “internal” organ Defined by a U-shaped epithelial lamina Urethra partially surrounded by clitoral stroma Erectile bodies absent in mouse, present in moles Typically located deep to preputial space May contain bone Lacks epithelial spines
Preputial space	Present in males and houses the penis Present in females and conveys urine to the exterior