SKULL OF RAN A TIGRINA. 



5 



The Parasphenoid (text-figs. 2 & 6, ps.) is of the typical form, 

 but unusually strong. The transverse limb lies under the 

 occipito -auditory masses. Its posterior border is deeply concave 

 and the ends of the transverse limb are considerably wider than 

 the portion near the middle line. The posterior median process 

 of the longitudinal arm is short and often elegantly pointed. 

 The anterior longer longitudinal arm, besides forming the floor, 

 rises up on each side to form a portion of the lateral wall of the 

 cranium. About the middle it is broader than at the ends. The 

 outer edges articulate with the prootics. the cartilaginous portion 

 of the cranium, and the sphenethmoid. The cartilaginous portion 

 of the side-wall of the cranium is relatively much smaller than 

 the anterior sphenoidal portion.. 



Text-figure 5. 



B. tigrina ; separated bones from the skull. 

 pm., premaxilla ; m., maxilla ; n., nasal ; fp., fronto-parietal ; s., squamosal. 



The Fronto-parietals (text-figs. 1, 3, and 5,^.) are adequately 

 described by Parker (4) in the following words : — 



" Above, the fronto-parietals form a strong roof with a 

 notch in front, the remains of the frontal suture, but are 

 wholly coalesced beyond this ; they end behind in two broad 

 wings which spread over the hinder region of the cranium 

 almost to the end. At first hollow in the middle, in the 

 postorbital region they develop a sagittal crest, which opens 

 out into two temporal wings. The temporal part dips into 

 the orbit and then rises over the ear-masses moulding on to 

 their sinuosities. The sides are notched, and the end has a 

 concave margin." 



