SERPENTS. 373 



occasionally lifting their heads above the surface to breathe, at tlie same time resisting 

 the efforts of the senior to free himself. Fislies and aquatic insects were refused, in 

 consequence of Avhich the young ones expired from inanition in the course of two 

 months." 



The family Rachiodontid-e is represented in Africa and possibly in Asia. iMsy- 

 peltis inornatus is frequently found under the bark of trees in the southeastern 

 portions of Africa and presents one of the most interesting examples of adaptation for 

 a special end. The Rachiodon has a general structure which enables it to lead an arbo- 

 real life, searching among tiie branches of the tropical trees for birds' eggs, and that 

 the contents of the egg may not be prematurely freed while it is yet in the mouth, 

 teeth are absent excejJt in the angle of the jaws where they cannot reach the shell. 

 When the egg reaches the a?sophagus it comes in contact with a row of " vertebral 

 teeth," formed by the specialized inferior spinous processes of the first seven or eight 

 cervical vertebrw, which are elongated and covered with enamel; by contraction of 

 the muscles of the throat, these saw through the egg, the contents passing on to the 

 stomach, while the limey shell is quickly ejected. Elachistodon loestermanni is the 

 Indian form. Though provided with the same peculiar vertebral teeth it is probably 

 a member of another family. 



The DiPSADiD^E, or night tree-snakes, includes a large number of serpents inhabit- 

 ing the tropical regions generally, ha\ing an elongated compressed body, broad and 

 triangular head, and with the posterior maxillary teeth grooved. In the Xew World 

 a single species passes north of Mexico into Arizona and Texas, though other repre- 

 sentatives are quite abundant further south, the genus Leptognuthus reaching the 

 Argentine Republic. Dipsas is found in Mexico and Brazil, as well as in India, 

 Africa, and Australia. It is from a most strange and ancient belief that the genus 

 has been thus named. Dipsas^ -which is derived from a Greek word meaning thirst, 

 was given to this harmless reptile from the belief that the animal was possessed of a 

 most insatiable thirst, to alleviate which it would often coil itself in the valuable 

 springs of the deserts, polluting their water and imparting to their victim, should 

 they sting the unfortunate traveler, an eternal thirst which could only be quenched by 

 death. 



Dlpsas dendrophila is of large size, sometimes measuring seven feet in length. It is 

 of a deep black color with numerous yellow cross-bars, which in some specimens are 

 reduced to lateral spots. The lower portions are usually yellow, marbled with black. 

 The species properly belongs to the East Indian archipelago, though it is occasionally 

 found on the mainland about the Malay peninsula. Of the Indian Dipsades proper 

 it is worthy of note that they capture only warm-blooded animals, some being exclu- 

 sively liird and others mammalian feeders. A single species, D. fuscus, inhabits 

 Australia, and a closely related form is found on the island of New Guinea. Though 

 the posterior maxillary tooth is long and grooved, the bite is not the least dangerous. 

 Being nocturnal in their habits, they are not so abundant in collections as are their 

 diurnal cousins the Dendrophidfe, though specimens have been taken all along the 

 eastern coast, where, coiled up in the branches of some tree, they await the ajiproach 

 of night, when they sally forth to search for birds' eggs, insects, frogs, and the 

 smaller Mammalia. In captivity they are said to be gentle, allowing themselves to be 

 freely handled without evincing the slightest inclination to resist. 



The blunt-head or Amhlijcejjhalus boa of Java, Borneo, and the neighboring 

 islands, though classified among the Dipsadidaj, is an aberrant form; the head has 



