250 XENOSAURIDZ. 
Fam. 7. XENOSAURIDA, 
Xenosauridee, Cope, Proc, Ac. Philad, 1866, p. 322. 
Trachydermi aglyphodonta, part., Bocourt, Miss. Se. Mew., Rept. 
1878. 
Xenosauride, Boulenger, Ann. § Mag. N. H. (5) xiv. 1884. 
Tongue short, villose, with a narrow, feebly incised, retractile 
anterior part covered with flat papille. Dentition strictly pleuro- 
dont; teeth numerous, small, with long cylindrical shafts, the 
laterals with obtusely bi- 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; premaxillary, 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 Jguanide and the An- 
guide. 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. KENOSAURUS. 
Xenosaurus, Peters, Mon. Berl, Ac. 1861, p. 453 ; Bocourt, Miss. Sc. 
Mex., Rept. p. 308. 
Central America. 
1. Xenosaurus grandis. 
Cubina grandis, Gray, Ann. § Mag. N. H. (2) xviii. 1856, p. 270. 
Xenosaurus fasciatus, Peters, 1. c. p, 454. 
grandis, Cope, Proc. Ac. Philad. 1866, p.322; Sumichrast, Arch. 
Se. Phys. Math, 1873, p. 243; Bocourt, lc. pl. xx. ¥. fig. 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 
