540 REPORT OF NATIONAL MUSEUM, 1898. 



adiposuui is present and free, except in certain Scincidse, where it is 

 wanting. The urinarj^ bladder is present, except in Teiidae, where it 

 is wanting. 



A colon is rarely present, and the alimentary canal is not very elon- 

 gate. The liver has usually but one or two notches behind, but there 

 are modifications to be mentioned under the heads of the respective 

 families. It is not elongate, except in serpentiform types. The ventral 

 mesentery extends as far as the liver, and sometimes a short distance 

 beyond. The transverse or cystic mesentery is present. 



The families differ as follows: 



I. Surangular bone distinct (mostly lacertiform). 



a. One premaxillary bone. 

 fj. No urinary bladder. 



Parietal bones coossified; temporal fossa not roofed with bone; no 



osteodermal plates 15. Teiidae. 



/3f3. A urinary bladder. 



Parietal bones distinct; temporal fossse with a bony roof; no osteo- 

 dermal plates 16. Xantusiid/E 



Parietals united; temporal fossse overroofed: no osteodermal plates 



17. Lacertid^. 

 Parietals united ; temporal fossae roofed ; osteodermal plates. 



18. Gerrhosaurid^. 

 aa. Two premaxillary bones. 



Parietals united; temporal fossse roofed ; osteodermal plates. .19. Scincid^. 



II. Surangular bone not distinct (serpeutiform). 



Two premaxillary bones; occipital" segment closely united with parietal; col-* 

 umella and arches present; eye distinct 20. Acontiid.e. 



Two premaxillary bones; no columella; no arches; eyes concealed by integu- 

 ment 21. DiBAMID.E. 



One premaxillary bone; occipital segment loosely attached; columella present; 

 no arches; eye concealed by the integument 22. AnelytropiDjE. 



Of these families the Xantusiidse and Teiidse are confined to the New 

 World and the Lacertida? and Gerrhosauridae to the Old World. The 

 Scincidae are cosmopolitan, abounding most in the warmer parts of the 

 South. 



XANTUSIID^. 



Xantiisiida' Baird, Proc. Acad. Nat. Sci. Phila., 1858, p. 254.— Boulenger, Cat. 



Liz. Brit. Mus., 2d ed., II, 1885, 

 Laeertidw Cope, part, Proc. Acad. Nat. Sci. Phila., 1864, p. 229. 

 Trachydermi aglyphodonta BOCOURT, part, Miss. Sci. Mex., Rept., 1878. 

 Lepidophiimiens Sumichrast, Bull. Soc. Zool. France, 1880, p. 178, 

 Xanttmidce Cope, Proc. Acad. Nat. Sci. Phila., 1883, p. 30. 

 XantusHdw Boulenger, Ann. and Mag. Nat. Hist. (5), XIV, 1884, p. 120. 

 Lepidophipnidw GiNTiiER, Biol. Cent.-Amer,, Rept., 1885. 



Tongue short, scarcely extensible, indistinctly nicked anteriorly, with 

 oblique overlapping plicae converging toward the median line, and scale- 

 like imbricate papillae on the distal extremity. Dentition strictly pleu. 

 rodout. Postorbital and supratemporal arches bony, strong, the supra- 

 temporal fossa roofed over by the cranial bones; pra^maxillary single; 

 nasals, frontals, and parietals two; palatines in contact with each other 

 anteriorly and with the maxillary and ectopterygoid, there being no 



