702 B. W. KUNKEL 



even in the adult of this form, the central cavity of the condyle, 

 in which the ligamentum apicis dentis is inserted, lies near the 

 ventral margin of the posterior surface of the condyle. 



REGIO OCCIPITALIS 



The occipital region, like that of Lacerta, maj^ be differentiated 

 into a basal and two lateral parts. A dorsal region is lacking, 

 although the tectum posterius, which is continuous with the otic 

 capsules, and hence properly belongs to the otic region, projects 

 caudally with its strongly developed processus posterior and closes 

 in the foramen occipitale magnum dorsally. 



The basal portion is represented by the basal plate including 

 the condylus and cristae inferiores (fig. 1), and the lateral parts 

 by the arcus occipitales, which are continuous ventrally with the 

 basal plate and extend freely dorsally, separated from the otic 

 capsules in front by the fissura metotica and not united distally 

 with the tectum posterius. Because of the separation distallj^ of 

 the arcus occipitales from the tectum, it is evident that at this 

 stage the fissura metotica and foramen occipitale magnum are 

 not completely separated from one another. 



The condj'lus occipitalis projects posteriorly as a cylindrical 

 process with convex ventral surface and flat, or even slightly con- 

 cave, dorsal surface so that a cross section is reniform. Its free 

 distal surface is flat except for a slight depression which extends 

 dorsally from the canal in which the chorda lies and gradually 

 deepens toward the dorsal surface of the condjde. The free end 

 of the condylus is embraced, except for a short space on the dorsal 

 side, by the atlas, which has the form of an incomplete ring and 

 projects forward ventral to the condyle as a stout process. 



In later stages the ossification of the condylus is seen to proceed 

 from three centers, one ventral to the chorda and one on each side 

 of it; corresponding to the basioccipitale and two pleuroccipitalia 

 respectively. 



The lateral portions of the occipital region are represented by 

 the arcus occipitales which arise from the dorsal surface of the 

 basal plate in the region of the foramina spiuo-occipitalia. The 

 arcus occipitales are stout, curved, sightly tapering prismatic 



