CROCODILIANS, LIZARDS, AND SNAKES. 539 



bead, and of osteodoiiiial plates on the bo<ly; to the latter by tlie stiuctuie of the 

 tougue, the teetb not hollowed out at the base, and the widely separated palatine* 

 bones. 



In Xenosaurus the alimeutary canal presents nothing exceptional. 

 There is no distinct colon, and hence no cfficnm. The liver is elongate 

 as in other Diploglossa, and the gall bladder is proximad to the margin, 

 and is just visible from below. The corpora adiposa do not project 

 freely into the body cavity. The kidneys are large. The mesenteries 

 are of the normal tyi^e. 



The hemipenis of Xenosaurus is quite peculiar. There are no calyc- 

 uli or flounces. There is a prominent fold with pectinate edge on each 

 side of the sulcus spermaticus, which incloses a pyriform area. This is 

 divided in the middle by a longitudinal fold, which represents the welt 

 opposite the sulcus of various other genera, and its distal end terminates 

 in a free papilla. From the apex there depend two large divergent 

 club-shaped papill;^, which have a series of points along the adjacent 

 sides. There is a small papilla at the base between them. The 

 arrangement has a remote resemblance to that seen in the Chamcdeon 

 'pardalis, and is unlike anything found in the other Diploglossa. 



The following are the characters of the only known genus : 



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 intermixed with tubercles, inferiorly 

 with cross rows of squarish juxtaposed scales; no bony plates. Digits well devel- 

 oped, with sharp, curved claws. No femoral pores. Tail round. . Xenosaurus Peters. 



But one species of this genus is known, the Xenosaurus grandis Gray, 

 a rather small Mexican lizard. The genus Exostinus Cope from the 

 White Eiver bed of Colorado resembles this one, so far as known, and 

 may enter the same family. 



LEPTOGLOSSA. 



Lepioglossa Gray, Cat. Liz. Brit. Mus., 184.5, p. .3. 



Leptoglossa and Typhlophthalmi Cope, Proc. Acad. Nat. Sci. Phila., 1864, p. 227, 228; 



Bull. U. S. Nat. Mus., No. 32, 1887, p. 25. 

 Lacertoidea Gill, Report Smithsonian Inst, for 1885, 1886, p. 800. 



Superior plate of petrous bone produced anterior to the anterior semi- 

 circular canal. Clavicles proximally dilated, usually perforated. Inter- 

 clavicle cruciform (with exceptions in degenerate forms). Frontal bone 

 not underarching olfactory lobes. Postorbital and supratemporal 

 arches present. Surface of tongue squamous or plicate, not papillose. 

 Hemipenis never calyculate. 



In addition to the above definitive characters, the following are gen- 

 eral, but with actual or possible exceptions. Surangular and angular 

 bones distinct from each other. 



Meckel's cartilage inclosed. Premaxillary not bounded behind by a 

 foramen on each side of the inferior plate. 



As regards the visceral anatomy, it may be said that the corpus 



