45. MICRVRUS 891 



Length to anus 367 



Length of tail 33 



Distribution. This species has been found north to 

 southern Utah and south in Mexico to Batopilas, in Chihua- 

 hua, and Guaymas, in Sonora. It has been taken on Tiburon 

 Island, in the Gulf of California. 



In the United States, it has been secured in southern 

 Utah, in Saint George Canyon, near the Arizona line. 



In Arizona, specimens have been collected in Cochise 

 (Fort Bowie, Fort Huachuca), Santa Cruz (Nogales), 

 Pima (Tucson, Mineral Hill, Rosemont, Sabino Canyon in 

 the Catalina Mountains), Gila (San Carlos), Yavapai (Fort 

 Whipple, Date Creek), and Mohave (Signal), counties, and 

 at Warsaw Mill on the Mexican boundary line. 



Although it seems to be restricted to the Lower Sonoran 

 Zone, its range in Arizona extends up to an altitude of at 

 least 5,000 feet. 



Habits. Unknown . 



Family 15. HYDRIDE 



This family comprises a number of genera of poisonous 

 snakes which are closely related to the Elafida? but are high- 

 ly specialized in adaptation to their marine life. Only one 

 genus, with a single species, occurs in American waters. The 

 tail is flattened from side to side, short and paddle-shaped. 

 The head plates are large. Both jaws are toothed. The per- 

 manently erect poison-fangs are near the front of the mouth, 

 as in the Elapdts. There are no rudiments of limbs or 

 pelvis. The eyes are small. The sea-snakes all are vivipar- 

 ous. Most of the species and genera are found in the tropi- 

 cal or semi tropical portions of the Indian and western Paci- 

 fic oceans. 



