74 BOID^. 



2. Scales smooth or imiearinate. 



Head covered with small scales ; rostral large. 



18. Eryx, p. 122. 



Head covered with small scales ; rostral moderate, deeper than 

 broad 19. Lichanura, p. 129. 



Head covered with large shields ; rostral large. 



20. Charina, p. 130. 



Siibfam. 1. PYTHONIN^. 



Pythoniiia, Oray, Zool. Miscell. p. 48, 1842. 



Holodontes (Pythonides), Bumdril ^ Bibron, Erp. Gin. vi. p. 381, 



1844. 

 Pythonina, Gray, Cat. Sn. p. 82, 1849. 

 Pythones, Loxocemi, Cope, Proc. Ac. Pliilad. 1861, p. 304. 

 Erycides, part., Pythonides, Jan, leoti,: Gen. Ophid. p. 64, 1864. 

 Loxocemina, Pythonina, Chondropythonina, Boulenger, Bull. Soc. 



Zool. France, 1879, p. 147. 

 Pythoninse, Chondropythoninee, Boulenger, Faun. Ind,, Sept. p. 244, 



Supraorbital bone present. 



1. LOXOCEMUS. 



Loxocemus, Cope, Proc. Ac. Philad. 1861, pp. 76 & 304 ; Bocourt, 



Miss. So. Mex., Rept. p. 614 (1882). 

 Plastoseryx, Jan, Arch. f. Nat. 1862, p. 242, and Icon. Gin. p. 65 



(1864). 



Prsemaxillary bone toothed. Anterior maxillary and mandibular 

 teeth longest, gradually decreasing in size. Head not distinct 

 from neck, covered with symmetrical shields ; rostral large and 

 projecting; no loreal shield, prsefrontals in contact with labials; 

 nostrils lateral, in a small nasal, which is separated from its fellow 

 by a pair of internasals ; frontal in contact with an azygous 

 occipital shield. Eye small, with vertical pupil. Body cylin- 

 drical ; scales moderate^ smooth. Tail short, conical, not prehensile ; 

 subcaudals in two rows. 



Mexico. 



1. Loxocemus bicolor. 



Loxocemus bicolor, Cope, Proc. Ac. Philad. 1861, p. 76 ; Giinth. 



Ann. 8f Mag. N. H. (3) ix. 1862, p. 55, and Zool. Bee. 1864, 



p. 123 ; Bocourt, Miss. 8c. Mex., Rept. p. 516, pi. xxx. fig. 5 



(1882). 

 Plastoseryx bronni, Jan, Arch. f. Nat. 1862, p. 244, and Icon. G4n. 



p. 66, 1. 3, pi. i, (1864). 

 Loxocemus sumichrasti, Bocourt, Journ. de Zool. v. 1876, p. 344. 

 brouni, Bocourt, Miss. 8c. Mex., Rept. p. 516, pi. xxx. fig. 6. 



Snout very prominent. Eostral broader than deep, the portion 



