BATRACHIANS AND REPTILES, CENTRAL AMERICA AND MEXICO. 57 



A loreal ; scales smooth Uromacir D. & B. 



yy. Form moderately elongate. 



A loreal ; scales smooth, with two pits Aisophis Cope. 



No loreal ; scales smooth Ocyophis^ Cope. 



/3/?. Two or more preoculars. 



Orbit resting on labials ; one loreal ; two anals ; two scale-pits Zamenis Wagl. 



Orbit surrounded by scales ; anal single ; two scale-pits ; one loreal .. . Pcriops Wagl. 

 Orbit surrounded by scales ; two or more loreals ; anal single ; two scale-pits. 



Chilolepis'^ Cope. 

 "Numerous small scales occupying the place of the frontals; " eye resting on scales. 



Spalero2)his Jan. 



Orbit resting on labials ; two anals ; one scale-pit Ti/ria^ Cope. 



One aual; no scale-pits • Zamenophis- Gthr. 



PIIILODKYADIN/E. 



A. Body rounded, not compressed. 



a. Scales grooved. 

 Crown and lores grooved ; one nasal ; two loreals Malpolon^ Fitz. 



aa. Scales smooth. 



Two loreals ; middle teeth equal Dirrhox' Cope. 



One loreal ; median teeth equal rkilodryas Wagl. 



One loreal ; median maxillary teeth long Jaltris Cope. 



aaa. Scales keeled. 



One loreal ; median teeth equal Trojndodryas Cope. 



AA. Body slender, compressed. 



a. Subcaudal scutella. 



Nostril normal ; two nasals ; two anals Chrijsopdea Boie. 



Nostril round in a single nasal ; two anals Ichtliiici/phns (itlir. 



Nostril semicircular, valvular DromopJih Pcf. 



aa. Subcaudal scuta. 

 Anal divided BucephaluH Sai. 



DllYOPHIDINyE. 



I. Middle maxillaries not elongate, posteriors grooved. 



a. An elongate nasal appendage. 

 Nasal and scuta undivided; scales keeled Langaha Brug, 



aa. No nasal appendage. 



Scales keeled Dryoplm-' Boie. 



Scales smooth J>ryinus Wagl. 



II. Middle maxillaries elongate ; posteriors grooved. 



a. An elongate nasal appendage. 

 Pupil horizontal Fassenia Gray. 



aa. No elongate nasal appendage. 



A loreal plate ; prenasals joined on the middle line Gephyr'muH^' Cope. 



A loreal plate; nasals not joined I'rayops Wagl. 



No loreal plate ; nasals separate Tropidococcyx Gthr. 



J'SAMMOPiriDINiE. 



Anal entire; a loreal Psammodmasiai Gthr. 



Anal divided ; a loreal Fsammojjhis Wagl. 



Nostril in prenasal ; no loreal Mimoplm («tlir. 



'Type T) romicus ater Gosaer. *Ccelopeltis Wnp}. Taphromrtopon Bvnndt. 



'^'i'yyie diiliiMer cliffordiii^ch]. ^ Thelotomi.'; Hmhh. (Hadophis Dmii. 



3 Type T. dahlii Fitz. •• Type Dryophis fronticincta Gtbr. 



'> Callirhinng Girard nee Cuvierij. 



