250 XENOSAURID^. 



Fam. 7. XENOSAURID^. 



Xenosauridfe, Cope, Proc. Ac. Philad. 1866, p. 322. 



Trachydermi aglypliodonta, part., Bocourt, Miss. Sc. Me.i., Rept. 



1878. 

 Xenosauridas, Boulenc/er, Ann. ^- Mag. K. H. (6) xiv. 1884. 



Tongue short, villose, with a narrow, feebly incised, retractile 

 anterior part covered with flat papillse. Dentition strictly pleuro- 

 dont ; teeth numerous, small, with long cylindrical shafts, the 

 laterals with obtusely hi- or tricuspid crowns : the new teeth origi- 

 nate between the bases of the old ones. Palate toothless. Post- 

 orbital and frontosquamosal arches bony ; supratemporal fossa not 

 roofed over by bone ; pra^maxillary, frontal, and parietal single ; 

 nasals distinct ; palatines and pterygoids widely separated medially, 

 both bordering the infraorbital fossa ; a supraorbital bone. Limbs 

 well-developed. Clavicle slender, not dilated proximally ; inter- 

 clavicle T-shaped; sternum without fontanelle. No abdominal 

 ribs. Head covered with small tubercular scales, which coalesce 

 with the skull. Eyelids well developed. Tympanum covered with 

 scales. Body depressed, covered above with granular scales inter- 

 mixed with tubercles, inferiorly with cross rows of squarish juxta- 

 posed scales ; no bony plates. Digits well developed, with sharp 

 curved claws. No femoral pores. Tail round. 



The unique genus, of which the preceding description is given, 

 constitutes a connecting link between the Ljuanida; and the An- 

 guidce. Its affinity to the former is shown by the T-shaped 

 clavicle, the absence of symmetrical bony shields on the head and 

 of osteodermal plates on the body ; to the latter by the structure of 

 the tongue, the teeth not hollowed out at the base, and the widely 

 separated palatine bones. 



1. XENOSAURUS. 



Xenosaurus, Peters, Mon. Bed. Ac. 1861, p. 453 ; Bocowt, Miss. Sc. 

 Mex., Rept. p. 303. 



Central America. 



1. Xenosaurus grandis. 



Cubina grandis, Gray, Ann. 4" Mag. N. H. (2) xviii. 1856, p. 270. 

 Xenosaurus fasciatus, Peters, I. c. p. 454. 



grandis. Cope, Proc. Ac. Philad. 1866, p. 322; Sumichrast, Arch. 



Sc. Phys. Math. 1873, p. 243; Bocourt, I. c. pi. xx. F. %. 1. 



Head depressed, subtriangular, covered with rough, subconical 

 or obtusely keeled tubercles, which form three longitudinal rows 

 between the orbits ; a slightly enlarged median occipital ; a series 



