XXII INTRODUCTION. 



genera Eutcenia, IFerodia, Eegina, and Storeria, are North American; Eeli- 

 cops and Hydrops are better represented in Central and South America. 



Although the family names in common use are retained here, they are 

 ranked as subfamilies of one great family, including all the Acaeophidia 

 or Colubrine snakes, the Colubrida?; The family Colvkrinae contains in the 

 genus Coluber several species very common in the United States: the Black 

 snake, C. constrictor, is found over a great portion of the continent, and the 

 section of the genus containing the Coach Whip snake (Masticophis), C. 

 flagelliformis, includes half a dozen species, from the Southern States, Mex- 

 ico, and as far south as Chili. Two species of the South American genus 

 Spihtes are found in the Gulf States. Pityophis, Cychphis, Phyllopkilophis, 

 and Salvadora ai'e North American. As the name Salvadora does not seem 

 to be used elsewhere in the animal kingdom, it has been retained. Promt- 

 cm is South American and West Indian, but contains one species peculiar 

 to the Southeastern United States and several others found in Southern 

 Mexico. The old world genus Elaplus claims several widely distributed 

 species from the southern half of the continent. 



Tachymenis, Erythrolamprus, Liophis, and Xcnodon arc South American 

 CoroncUhuv, and are represented by a few species in the southern part of 

 Mexico. Ophibolus, Diadophis, Heterodon, Bhinocheilus, Cemophora, and /////*- 

 siglena are classed as North American; the first three are found in all 

 the States, with, perhaps, a few exceptions in the northern tier. 



The CalamarincB, of the genera TantUla, Contia, Sonora, Virginia, and 

 Carphqphis are Northern; Ficimia, CAeilorhina, Stenorhina, Ninia, Creophis, 

 and Elapomorphus are shared by Mexico with South America. 



Tree snakes are found in the Dipsadince, Scytalince, Dendrophince, and 

 Colubr'nm ; water snakes in the Natricinoe ; and ground snakes in the 

 Calamarince, Corpnellince, and Colubrince. But in each family there are 

 species whose habits are so uncertain as to render their positions doubt- 

 ful. 



Toxicophidia. 



Grouping all the venomous serpents in a single suborder, brings together 

 animals of considerable diversity. Because of their differences they have 

 been arranged in various sections : one, the Proteroghjpha, in which the 

 fangs are erect, immovable, and grooved in front ; and another, the Solen- 

 oglypha, which are distinguished by an erectile perforate fang. The Pro- 



