720 EEPOET OF NATIONAL MUSEUM, 1898. 



RHINO PHID.E. 



T. Tail ternuniitiug in a large shield. 



Rostral plate produced posteriorly, separating the nasals.. .Ehinophis Hemprich. 



Rostral not produced; nasals in contact Uropeltis Cuvicr. 



II. Tail scaly to end. 



a Eye in the ocular shield. 



Tail terminating in a disk of keeled scales; sup. .lorhitals and postocular 



confluent StUjbiu-a Giinther. 



Tail compressed, truncated, terminating in a bicuspid scale, the points super- 

 posed; postocular distinct Plectritrns Dunu'ril and Bibrou. 



Tail with smooth scales, terminating in one or two points; jiostocular united 



with superciliary; a median chin groove Melanophidium Giinther. 



,a Lx Eye between the surrounding shields. 



Tail tapering, terminal scute ending in a horizontal ridge; no chin groove 



PlaUjplectritrus Giinther. 

 Tail tapering, ending in a single point; no chin groove. . Teretrurus Beddome. 



No species of the Rliinophidse has been discovered out of the Palaeo- 

 tropic realm. 



COLUBROIDEA. 



Five well-marked divisions are embraced in this suborder, as follows: 



I. Chevron bones with distinct hjemapophyses. 



Rudimental posterior limbs; no grooved teeth; generally two lungs.. Peropoda 



No rudimental limbs or grooved teeth ; one lung rudimental Aglyphodonta 



No rudimental limbs; a posterior maxillary tooth or teeth, grooved; one lung 



rudimental Glyphodonta 



No rudimental limbs; an anterior tooth with a tube for poison duct; one lung 



rudimental Proteroglypha. 



II. Chevron bones complete, forming hjemal spines. 



No rudimental limbs; a tubular tooth in front of mouth; one principal normal 

 lung and a tracheal lung Platycerca. 



It is questionable whether the Aglyphodonta and Glyi)hodonta 

 should be retained as distinct from each other. Most of the penial 

 characters found in the one occur in the other, and it remains to ascer- 

 tain whether these, or the grooving or not of the teeth, are to be con- 

 sidered to be of primary importance. For the present I follow the 

 example of Dum^ril and Bibron, and Boulenger. 



PEROPODA. 

 I find here three distinct families, as follows: 



Two pulmonary lungs, no tracheal lung; nasal bones distinct; a corouoid bone; 



lieminenis jdicate ^. BoiD.*;. 



Two pulmonary lungs; no tracheal lung; nasal bones coosifled; no coronoid bone; 



hemipenis plicate Chauinid.e, 



One pulmonary lung; a tracheal lung; two nasal and a coronoid bone; penis 



smooth Ungaliid^.' 



' Cope, Proc. Amer. Phil. See, 1894, p. 220. 



