RHYNCHOCEPHALIA. 



331 



, The dentition is acrodont, and the teeth are fused with the 

 subjacent bone. Tlie premaxillary teeth, and the downwardly 

 curved premaxillae with which they are fused, have the appear- 

 ance, especially when worn down, of a pair of rodent-like incisors. 

 There is a row of small triangular teeth on the maxilla and 

 another on the palatine. The single row of mandibular teeth 



Frf 



j'lf Por I'a 



Fig. 182.— Sphenodon pimctaius, skull A from the side B from above. C from below, D from 

 behind (after Gilnther, from Zittel). A orbit ; Ang angular ; art articular : Bo basi- 

 occipital ; Ch internal nares ; d dentary ; Exo exoccipital ; Fr frontal ; Jv jugal ; K sur- 

 angular ; Mx maxilla ; N external nares ; JVa nasal ; Opo opisthotic ; Pa parietal : PI 

 palatine ; Pmx premaxilla ; Por postorbital ; Pri prefrontal : Pt pterygoid : Ftf postfrontal ; 

 Qu quadrate ; Qu Jii quadrato-jugal ; S superior temporal fossa ; Sq squamosal ; So supra- 

 occipital ; Vo vomer. 



bite between these two rows in the upper jaw. In some young 

 specimens there are a few small teeth on the vomers. The 

 pterygoids are edentulous. 



There is a T-shaped interclavicle and a clavicle, and the cora- 

 coid is without fenestrae. The humerus has an entepicondylar 

 as well as an ectepicondylar foramen. The carpus has ten 

 separate bones. The pelvis is somewhat lacertilian though the 



