Fig 4.

3D models of Pipistrellus pipistrellus penes. 3D surface renderings of manually segmented tissues overlaid on volume renderings of a flaccid (top) and an inflated (bottom) P. pipistrellus penis. Gray arrows mark where the corpus spongiosum is enveloping the baculum. White arrows mark the area where the baculum and corpora cavernosa are linked. Black arrow shows the urethral opening. Orange: outer shape of the penis (volume rendering), white: baculum, red: blood lacunae in the corpora cavernosa, green: tunica albuginea of the corpora cavernosa, blue: urethra, pink: corpus spongiosum.