Ventral surface of Skull of Frog
i) Skull is triangular, dorso-ventrally flattened, and broad.
ii) Skull is dicondylic i.e two occipital condyles.
iii) Occipital region is greatly reduced.
iv) Premaxilla, maxillae, quadrato jugals, vomers,palatines, sphenoethmoidal, parasphenoid, pterygoids and ex-occipitals bones can be seen.
Ventral surface of skull of Varanus
i) The skull is compact and more or less elongated having the narrow anterior end.
ii) It is monocondylic i.e single condyle is borne by the basioccipital which articulates, with the atlas vertebra.
iii) It is triploblastic.
Ventral surface of skull of Fowl
i) The cranial portion comprises cranium proper auditory and capsules while the facial portion comprises olfactory capsules, upper and lower jaw and hyoid apparatus.
ii) Occipital region is formed of the basioccipital below, the occipitals on the sides and supraoccipital above and enclosing a central foramen magnum.
Ventral surface of skull of Rabbit.
i) Cranial portion is small, while the facial portion is elongated and somewhat deflected.
ii) Occipital region comprises four bones i.e two ex-occipitals, one basioccipital and one supraoccipital.
