780 REPORT OF NATIONAL MUSEUM, 1898. 



66. Inl eruasals not fused with uasals. 

 Rostral trihedral ; internasals present ; anal entire ; calyces 



not fringed Ceinophora Cope. 



Rostral recurved ; no internasals; calyces numerous, fringed; 



anal divided Ficimia Gray. 



Like Ficimia, hut internasals present, separated hy rostral. 



Gyalopimn Cope. 

 Rostral not recTirved; nasals distinct from labials; calyces 



numerous Geagras ' Cope. 



Rostral not recurved; nasals distinct from labials; calyces 



very few Conopsis Glinther. 



CC. Rostral plate free laterally ; pupil erect. 



Colubriform, subisodont PhyUorhynchus Stejneger. 



^/3. Hemipenis capitate. 



Pupil round; rostral free laterally Salvadora Baird and Girard. 



Pupil erect; rostral normal Hypsifjlena Cope. 



aa. An awn-like apical papilla. 



Colubriform ; scuta normal Cynophis Gray. 



AA. Calyces with the borders spinous. 



Colubriform ; isodont ; scuta normal Gonyosoma Wagler. 



AAA. Calyces with spines on the internal walls. 



Calyces numerous, fringed; scutanormal; one nasal -plate.. En tacaiithus^ Cope. 

 ** Calyces split up into papilla?. 



A preocular ; one prefrontal Trimetopon Cope. 



No preocular ; two prefrontals Adelphicits Jan. 



II. Anterior hypapophyses piercing the walls of the oesophagus. 

 a. Spines in transverse or flounced rows. 

 Calyces numerous, fringed ; scutanormal; one nasal; dipsadiform. 



Dasypeltis Wagler. 



This subfamily includes the grouud snakes wbicli are characteristic 

 of the two great northern land areas, Eurasia and North America, but 

 numerous species occur iu the regions to the southward, especially in 

 the Oriental and Neotropical realms. The dentition is isodont or cory- 

 phodont, between which no line of demarcation exists, although a few 

 forms {Zanienis for example) present in some of the species the dia- 

 cranterian type. In a few (for example, Binodon) the median teeth are 

 longer than those that immediately follow them. In this subfamily, as in 

 most of tbe others, a tendency to a burrowing habit and fusiform shape 

 api^ears. The beginning of this is seen in Coronella, and iu Ophibolus, 

 and it becomes very pronounced iu a number of genera which inhabit 

 the warmer parts of North America and the Central American district 

 of the neotropical realm. All the truly burrowing genera of the Colu- 

 brinse are American, and they display affinities to genera in which this 

 habit is less marked. Thus the burrowing Stylosoma is related to 

 Ophibolus of the spotted type and Cemophora to the annulate type of 

 the allied genus Osceola. Otlier fusiform burrowing genera are Ghilo- 

 menisciis, Geagras, Conopsis, and Ficimia. 



On the other hand, the passage to arboreal types is easy. In the 

 Oriental region Bendrophis is the typical tree snake, and in Africa we 



' G. frontalis Cope, examined. 



'^Type, Cyclopliis major Gunther; Chiua. 



