SERPENTS. 369 



well as of other innocuous ophidians, is present, and the assumeil shape of the body 

 when the animal is angry is compressed, instead of dei>ressed like that of venomous 

 forms, of which tlie laterally extended neck of the JVifJa jiresents the best type. 

 It seldom attempts to bite, and can be ordinarily handled without showing any re- 

 sistance. The food consists of batrachians, saurians, yoinig birds, and possibly 

 insects. It is probably oviparous, and is found in all but the southern portion of the 

 Australian continent. D. callif/aster is a more northern form. It is small, not reach- 

 ing a length of three feet, has no loreal shield, and below is purplish-yellow. 



Chrysopelea orna, because of the innumerable varieties of marking which it 

 presents, almost defies sjieeific descrijition. It is considered by Giinther to be the 

 most beautiful of all snakes. In its habits it is arboreal, being able to even pass 

 down a smooth and vertical tree-trunk. It is a widely-distributed form, inhabiting 

 southern Asia and the East Indian archipelago. Its food consists of geckoes and 

 other small saurians. 



The family DRYOPurD.-E includes some of the most interesting forms of the serpent 

 tribe. In the genus Dri/ophis, not only is the body so slender and elongated as to 

 reach a length of nearly five feet, with a diameter of less than an inch, but the head 

 is also slender, with the muzzle projecting for some little distance as a pointed pro- 

 boscis. Representatives of this group are found in Asia and America, though the 

 most interesting form inhabits Madagascar. The Old World species have the maxil- 

 lary teeth grooved, while the American forms have them less specialized. The preva- 

 lent color is green, with two longitudinal white stripes along the lower side. The 

 longer diameter of the pupil is horizontal, a position which jiossibly points to the 

 noctui'nal habits of the animal. 



The most remarkable representative of the family is the langaha, Dryophis lanx/aha 

 of Madagascar, which, though its body is less than three feet long, has a scaly proboscis, 

 often flattened into a leaf-like organ, half an inch in length. The general color of the 

 animal is a deep brown. Trctffojis pi-cisinus, or as it is sometimes called, DryojMs 

 7iasutiis, is a beautiful grass-green animal, living in the jungles of India, and often 

 reaching the length of seven feet. To it has been attributed the habit of darting at 

 the eyes of passers-by, an action which has made it particularly disliked by the na- 

 tives. The snout is greatly prolonged, and provided with a movable fleshy tij>. 



Passerita has the snout much produced, as in langaha. That this develojiment is 

 used merely as a tactile organ, such as are the tentacles of Ilerjieton, is questionable. 

 While Herpeton is semi-aquatic, and would find tentacles, which would do away with 

 the necessity of it protruding its tongue, a most useful acquisition, Passerita is an 

 ordinary tree-snake in its habits, so that its tongue can, unhindered, perform its ordinary 

 functions. The rostral prolongation is moreover covered with rough scales, and can 

 only be imperfectly sensitive. It seems that the true oflice of this development is to 

 increase the size of the opening of the mouth, as do the marginal bristles of the 

 mouth of some birds — for example, the night-hawks (Caprimulgidai). 



The Natkicid-e, which includes many of our most common snakes, unites forms so 

 diverse that clear definition is almost impossible. It includes serpents which may be 

 small or large, slender or stout ; the eyes are of medium size ; the teeth variable ; and 

 the scales either keeled or smooth. The several genera are well circumscribed, though 

 the family is difficult to define. They i)refer the neighborhood of water, in which, if the 

 case demands it, they are expert swimmers. They differ from many other Colubriform 

 snakes in their habit of beginning the process of deglutition as soon as their ))rey ia 

 VOL. III. —24 



