Figure 2: A and B Embryo at gestational day 14 featuring forelimbs and hindlimbs shaped like "paddles" and shallow grooves indicating the beginning of digit formation. C An embryo at gestational day 14.5 to 15; note the external ear (Ee) and the pinna covering the ear canal, eye (E) pigmentation, and oral cavity (Oc). D Fetus at gestational day 17.5; note the well-developed mandible (M), the vibrissae (V), and the nasal region (Nr). E Fetuses at gestational days 18 and 18.5; notice the open oral cavity (Oc), mandible (M), nasal cleft (Nc), the vibrissae (V), and further developed nasal region (Nr). F Fetuses at gestational days 19 and 19.5; note the more developed genital tubercle (Gt) at this age, making it possible to distinguish sex.