Cope.] 212 [March 18, 



posterior limb expanded. Postfroatal and postorbital fused into a trian- 

 gular bone which bounds the parietal externally, thus, with the supra- 

 temporal, roofing over the temporal fossa. Supratemporal in contact 

 throughout with the parietal except where separated by the narrow sphnt 

 of a p-iroccipital. Quadrate with one, a large external conch. Vomers 

 closely juxtaposed throughout, coossifled anteriorly, the median por- 

 tion of the two elements with an excavation. Nareal orifices nearly 

 closed except posteriorly, wliere the vomerine process of the palatine 

 overarches them. The latter are in contact in front but soon spread 

 apart. Maxillary processes rather shorter than vomerine, depressed be- 

 low them. Pterygoids narrow throughout, not wider than palatines, 

 their posterior part with a groove which looks upvvards and inwards. 

 Basipterygi)ids overlapping their entire internal face. Ectopterygoids 

 wide, reducing the palatine foramen to a mere slit ; with a considerable 

 contact with the palatine, and a recurved portion in contact with the ex- 

 tremity of the maxillary ; the internal extremity depressed. No presphe- 

 noid ; sphenoid separated by suture from basioccipital, whose lateral pro- 

 cesses are compressed and decurved. The postoptic bone seems to be 

 wanting. The petrosal is well produced beyond the semicircular canal, 

 and is equally produced below the trigeminal foramen, where it joins a 

 backwards directed process of the basipterygoid. The groove below it is 

 well defined and looks downwards. The epiplerygoid rises at the basi- 

 pterygoid and rests on the anterior border of the petrosal and the poste- 

 rior border of the well-marked descending process of the parietal. Fen- 

 estra ovale not sunk in the lundus of a fossa. 



The mandible is remarkable in having but three bones. The articular, 

 angular and surangular are coossifled, and thesplenial and dentary. The 

 coronoid has little horizontal production on the outside of the ramus, and 

 the angle of the dentary extends considerably posterior to it. The Mecke- 

 liau groove is entirely closed. 

 The hyoid apparatus is described under the head of the genus Xantusia. 

 There is no zygosphen. There are six cervical intercentra besides that 

 of the atlas. The cervical ribs commence on the fourth vertebra. Four 

 of these ribs are of peculiar form, being expanded and truncate at the 

 extremity so as to be somewhat fan-shaped. Neural spines rather low on 

 the cervical and caudal regions, and lower on the dorsal vertebrae. Cau- 

 dal vertebrae segmented towards the anterior part, the fissure passing 

 through the middle of the diapophyses. Neural spine single, oblique, 

 posterior ; chevron bones normal. 



Suprascapula short and wide ; scapula without proscapula. Coracoid 

 with one notch ; sternum without fontauelle. Interclavicle with moder- 

 ate posterior limb. Sternal ribs three ; xiphoid rods not juxtaposed, 

 supporting two ribs. No abdominal ribs. 



Pubes meeting at about a right angle ; pectineal angles near the mid- 

 dle, decurved. Pubis with tuber exterior. Ilium without angulus cristse ; 

 acetabulum entire. 



