Zoology(External Features of the Frog & Buccal Cavity)
The body of the frog may be divided into:
Two pairs of Appendages
Eyes – located posterior to the nostril.
Upper Eyelid – borders the dorsal side;
Lower Eyelid – borders the ventral side;
immovable, thinner than upper eyelid.
Third eyelid (nictitating membrane) –
allows the frog to see underwater. Serves to
moisten the eyes when it is on land.
Brown spot – circular spot at the
anterior level of the eyes.
Ears – Tympanic Membrane – covering the
eardrum; They are basically engaged in
transmitting the sound waves to the inner ear,
so that it gets protected from water and other
Snout – the anterior blunt tip of the head.
External Nares – paired opening located at
the snout connected to internal nares
Anus or Vent – the most posterior opening
found at the median and posterior end of the
Forelimbs – used to raise or support the body
when the frog is at rest. Three divisions:
brachium (upper arm), antebrachium
(forearm), manus (hand).
Hindlimbs – well adapted for jumping and
swimming. Three division: thigh (upper leg),
shank/crus (lower leg), pes (long foot).
Foot – divided into tarsus (long ankle),
metatarsus (instep), and five fully-webbed
toes or digit.
Male frog vs. Female frog
Male is smaller than female.
Male has a black band or dark pigment area
at the ventral surface of the lower jaw.
During breeding season, male’s forelimbs
differ from that of the female.
The forearm of the male is relatively thicker
due to a great muscular development in
The inner digit or thumb of the hand of the
male is larger and swollen at the base due to
the glandular secretion of the skin.
a. Esophagus opening.
b. Vomerine teeth.
1. Grove of the maxilla.
2. Maxillary teeth.
3. Internal nare.
4. Eye ball.
5. Eustachian tube opening.
6. Jaw ridge.
7. Underside of the tongue.
9. Cut muscle and bone.
Orbits or eyesockets – pair of rounded
Internal or Posterior Nares – frog can breath
through these with it's mouth closed, can be
opened or closed with sphincter muscles.
Vomerine Teeth – located between the internal
nares, serve to prevent the escape of prey.
Maxillary Teeth – fine saw like teeth. For
holding the prey.
Sulcus Mariginalis – marginal groove internal to
maxillary teeth. Receives the lower jaw.
Pulvinar Rostrale – low elevation at the side
of the median subrostral fossa.
Median Subrostral Fossa – depression in the
sulcus marginalis. Located at the tip of upper
Lateral Subrostral Fossae – depression on
each side of the pulvinar rostrale.
Eustachian Tube – equalize pressure in the
Vocal Sac – only in males, can be inflated
with air to make the mating call.
Hyroid Cartilage – where the tounge and
other muscles are attached and which
continously moves during respiration.
Bilobed Tongue – covered with sticky
secretion can be readily extended and
Tuberculum Prelinguale – located at the tip of
the lower jaw. Fits into the median subrostral
Prelingua Fossa – depressions on either side of
Glottis – narrow slit of larygeal
prominence; leads into the lungs.
Esophagus (gullet) – passageway for good,
from the mouth to the stomach.