Description of a New Plesiosaur. 



311 



out. As usual the posterior part of the parietals, probably together 

 with the parietal processes of the squamosal, project some distance 

 behind the occipital surface. 



The basi-splienoid is concealed by the overlapping pterygoids and 

 by the posterior end of the parasphenoid. This latter (pas.) is a 

 narrow vertical plate, not a horizontal one, as in Murcenosaurus and 

 Cryptocleidus. As in the other Plesiosaurs, it divides the posterior 

 inter-pterygoid vacuity into two openings (p.i.v.) (elsewhere called 

 the posterior palatine vacuities). Its anterior end is thrust between 



S.OV: 



in. 



FIG. 1. 



1. Diagrammatic view of the palate of Plesiosaurus capensis. \ nat. size. 



a.i.v., anterior interpterygoid vacuity; fr.oc., basi-occipital ; i.n., internal 

 narial openings; w.r., maxilla; pal., palatine; pas., parasphenoid; p.i.v., 

 posterior iriter-pterygoid vacuity ; pin.r., premaxilla ; pt., pterygoid ; 

 (/..quadrate; s.o.v., sub-orbital vacuity ; ?., transpalatine bone ; r., vomer. 



the palatine plates of the pterygoids, but its exact limits are obscure. 

 The pterygoids (pt.) are of the usual triradiate form : posteriorly 

 they unite with one another in the middle line beneath the basi- 

 occipital and basi-sphenoid, and are produced backwards and out- 

 wards into thin vertically compressed processes to the quadrates. 

 In front of their union beneath the basis cranii the median borders 

 of these bones diverge from one another and enclose a large oval 

 inter-pterygoid vacuity (p.i.v.) which, as just mentioned, is divided 

 into two in the middle line by the parasphenoid. In front of this 

 vacuity the anterior end of this bone is wedged in between the 



