822 PROCEEDINGS OF THE ACADEMY OF 



Two pneoculars, three loreals, not separated by the single pos- 

 terior can thai ; prenasal in contact with first labial. Tail 

 2 - 75 times head and body ; extended limbs separated by 

 length of humerus ; red with ten light cross bands, v-shaped 

 backwards ; belly not black spotted ophiurus. 



Three loreals, posterior canthal divided, each half correspond- 

 ing to a loreal ; prenasal separated from contact with first 

 labial ; tail twice head and body. Light olive with seven or 

 eight dark cross bars ; below yellowish marbled with olive., infernalis. 



The first species is Pterogasterus ventralis Peale and Green, Journal Acade- 

 my, yi. 233. 



The G. ophiurus is 13 inches in length. 

 Habitat. Orizava, Mexico, Prof. F. Sumichrast. 



Xenosaurus grand is Gray, Cubina grandis Gray, Ann. Magaz. Nat. Hist, 

 xviii. 270. Xenosaurus fascia tus Peters, Monatsberichte Berlin Acad. 



The genus Xenosaurus, first defined by the able Zoologist of the University 

 of Berlin, is of much interest. Prof. Peters referred it with doubt to tlie Helo- 

 dermidse, and in my system of the Sauria,* 1 have followed his suggestion, not 

 having had the opportunity of studying its skeleton. This having been 

 afforded by the specimens sent to the Smithsonian Institution by F. Sumichrast, 

 my conclusion regarding it is as follows : It is a Diplogloss in all points, pre- 

 senting the anomaly of very strong inferior frontal crests, which fail of under- 

 arching the olfactory lobes of the brain, approaching in this respect equally 

 the Gecconidse and Varanidse. The anterior limb of themesosternum is shorter 

 than in most of the Diploglossa. Parietal fontanelle distinct. The Xeno- 

 sauridse will stand in the system between the Gerrhonotidse and Heloderniidae 

 with the following diagnosis : 



No premaxil/ary foramen, dentition strictly pleurodont, teeth with elongate 

 cylindrical shanks attached on inside of alveolar parapet ; head tubercularly 

 scaled, temporal fossa not over-roofed by dermossif cation ; mesosternum cr%ici~ 

 form. 



While the characters of the Helodermidse are : 



No premaxillary foramen ; teeth with short dilated bases, obliquely anchylosed ; 

 head tubercularly scaled, temporal fossa overarched by dermoossification ; mesos- 

 ternum ivithout lateral limbs, longitudinal. 



The supraorbital ossification in Xenosaurus is a triangular piece over the 

 anterior third of the orbit, attached to the prefrontal bone, not as in the other 

 Diploglossa, continued to the postfiontal. The ball of the eye is defined by 

 fourteen flexible sclerotic plates in front, whose contact is valvate except round 

 the pupil, where each one dilates and overlaps the next, forming an imbricate 

 circle. 



Sceloporus heterurus sp nov. 



Four and five rows of supraorbitals besides the internal and external margi- 

 nals. But little difference in size of dorsal, 'ateral and abdominal scales, the 

 first with strong keel and mucro, not serrate, in 45 transverse rows between 

 interscapular and sacral regions. Caudal scales much larger, with elevated 

 keels continued as ridges, in eighteen longitudinal rows 8 lines beyond vent. 

 Head scales smooth, the anterior frontal not divided ; occipitals distinct. Some 

 large marginal scales in front of auricular meatus. Femoral pores seventeen. 



Color bright leek green with numerous delicate brown lines directed 

 obliquely forward towards the back and there turning backwards ; a narrow 

 line ascending from arm to interscapular region receives a longitudinal one 

 from orbit; a longitudinal line in front of thigh. 



Total length 6 in.; from muzzle to vent 2 in. 6 1. 



* Proceedings Academy, 1S64. 228. 



[Nov. 



