FAMILIES OF LIZARDS. 649 



OKDER LACERTILIA. LIZARDS. 



Sauria, Mitart, Milne Edwards. 



Body usually laoertiloid, in some species serpentiform ; feet usually four, sometimes 

 two, and oooasionally none; anal slit transverse; body covered with scales, tubercles, 

 or spines ; top of head with plates ; eyelids usually movable ; teeth conical, no,t in 

 sockets ; heart with auricles and a. ventricle, the septum in the latter incomplete ; 

 urinary bladder present ; vertebrjB procoelous except in the Geckos a.nd Sphenodon where 

 they are amphicoelous ; saorals separate, sometimes one, and never exceeding two in num- 

 ber ; head of ribs simple, undivided ; sternum present except in the serpentiform species ; 

 quadrate bone somewhat movable ; rami of the lower maxillary usually firmly united ; 

 alisphenoids and orbitosphenoids absent or rudimentary : parietal foramen usually dis- 

 tinct ; parotic processes long ; hyoid a median rod. 



The Lacertilia comprise a large order, with numerous species and families. Those 

 inhabiting North America may be arranged as follows : 



* Bones of skull grown together; dorsal region covered with square plates; genera- 



tive organs simple ; feet rudimentary or none, . . . Amphisbaenid^. 



* Bones of skull distinct ; dorsal region usually scaly ; penis and vagina bifid ; feet 



usually well developed, a. , 



a. Tongue flat, elongate and bifid, i. 



a. Tongue thick, convex, attached at base to cesophagus. c. 

 6. Abdominal region covered with roundish scales, quincuncially arranged and 



resembling those of the back. d. 

 6. Abdominal region covered with square plates, e. 



0. Dorsal scales granular ; eyes large, almost without lids. . GECKOTlDiB. 

 u. Dorsal scales imbricated ; eyes moderate ; lids distinct. . . Iguanid.S!. 

 d. Eyes and eyelids nearly or quite concealed. /. 



d. Eyes and eyelids prominent. SciNClD.*:. 



e. Teeth solid ; cephalic shields large, g. 

 e. Teeth hollow or grooved behind, h. 



f. Head conical ; rostral cup-shaped TYPHLiNiD^a;. 



/. Head depressed ; rostral elongated Typhlopsid^. 



g. Sides flatteoed, without lateral fold. h. 



g. Longitudinal lateral fold or stripe present, i. 

 h. Cephalic shields small. . ... HBLODBRMiD.a;. 



h. Cephalic shields large, regular. I. 



i. Ear distinct, j, 



i. Ear concealed. . . .... Cbalcid^s:. 



j. Limbs two or none ; body serpentiform ; no femoral pores. ANGUiDiB. 

 j. Limbs four ; body more or less lacertiloid. . . . Zonurid.*!. 



I. Supraorbital plate bony. ..... Lacertid.*;. 



I. Supraorbital plate horny. .... . TsiDiE. 



Of these families, Amphisbaenidie has one genus Ehineura, with one species, /oridana, 

 inhabiting Florida ; GeckotidoB has four, Coleonyx, S^liarodactylus, Fhyllodactylus, and 

 Di^lodactylus, of which Sphoerodactylua notatus occurs in Florida, the remainder range 

 from Texas to the Pacific coast ; Typhlinidro has Aniella pulchra in California; Typhlop- 

 Bida3, one genus, Stenosloma, with two species ranging from Texas to the Pacific ; Teidse 

 has CnemidopTiorus and Veriicaria ; Helodermidis has Heloderma horridum in Mexico ; 



