A. Head – most anterior, triangular part w/c is flattened dorso-ventrally
1. Snout – blunt apex of the head
2. Mouth – large anterior opening w/c extends postero-laterally up to the head’s base
> dorsal & ventral lip folds – immovable folds that border the mouth dorsally & ventrally
– provided w/ valves w/c are associated to respiratory movements
– provided w/ valves w/c are associated to respiratory movements
3. External nares or nostril – pair of slit-like openings immediately postero-lateral to snout
4. Eyes – pair of large structures w/c protrude on the dorso-lateral sides of the head and posterior to the nostrils.
> Upper Eyelid – thicker structure; borders the eye dorsally; very little movement
> Lower Eyelid – thinner structure; borders the eye ventrally; more movable
> Third Eyelid or nictitating membrane – thin, transparent, freely movable membrane w/c continuous w/ the inner fold of the lower eyelid. – homologous to the vestigial PLICA SEMILUNARIS – a fold like structure located near the median corner of the human eye.
> Orbit or eye socket – socket where eyes retract
> Cornea – exposed transparent part of the eye
> Conjunctiva – thin transparent membrane w/c is continuous w/ the inner surface of the eyelids.
> Conjunctiva – lies and inseparably adheres to the outer surface of the cornea
> Pupil – dark, centrally located opening through w/c light can enter the eye
> Iris – pigmented, curtain-like structure w/c surrounds the pupil
> Iris – regulates the size of the pupil depending upon the intensity of light
> Browspot – small, lighter-colored circular spot at about the anterior level of the eye
> Tympanic membrane (Tympanum) – smooth, somewhat circular, thin membrane, postero-lateral to the eye.
B. Trunk – much bigger part of the body & is situated posterior to the head, having no distinct neck
1. Hump – distinct dorsal elevation about the middle of the