272 OPHIDIA. 



Tkopidonotus plumbicoloe. 



Tropidonotus plumbicolor. Cantor, Proc. Zool. Soc. 1839, p. 54. 

 Xenodon viridis, Dimi. ^" Bibr. vii. p. 763. Gi'mth. Colubr. Snakes, p. 57. 



Head broad, body stout, tail short. Scales in twenty-five rows, sometimes in twenty-three 

 or twenty-seven. Ventrals 160-161; subcaudals 42. Two prte- and three post-oculars. 

 Seven upper labials, the third and fourth entering the orbit ; temporals 2 + 3. Vertical five- 

 sided, anterior margin as long as lateral ; occipital not twice as lai'ge as vertical ; anterior 

 frontal more than half as large as the posterior; the praeorbital scarcely reaches to the upper 

 surface of the head. Each maxillary is armed with eight small teeth, and with a very long 

 posterior one separated from the others by a considerable interspace. Dirty greenish : 

 } oung specimens with a broad white collar, pointed in front and forked behind, preceded by 

 a similar black spot, the point of which extends to the vertical shield and is edged with black 

 behind ; an oblique black streak behind the eye ; trunk with ten or eleven narrow black 

 cross bars, and generally with a black lateral spot in the middle of the interspaces of the 

 cross bands. Sides of the throat dotted with black ; belly more or less blackish. All these 

 markings generally disappear with age, with the exception of an oblique, more or less distinct 

 l)lackish band on each side of the neck, — the upper parts being uniform dirty green, the 

 lower whitish. 



This species is not uncommon in the Madras Presidency, and frequently enters houses ; it 

 attains to a length of 25 inches, the tail measuring 3 inches. 



ATRETIUM. 



Atretium, Cope, Proc. Acad. Nat. Sc. Philad. 1861, p. 299. 



Body cylindrical, rather stout ; head narrow ; eye of moderate size, with 

 round pupil. The anterior frontals are united into one triangular transverse 

 shield, which is in contact with the rostral. The other shields of the head 

 are regular. Two nasals ; the nostril is in the upj)er part of the suture 

 between them, but on the side of the head. Scales rather short, rhombic, 

 keeled, in nineteen rows. Ventrals broad, rounded; anal bifid; subcaudals 

 two-rowed. Teeth numerous, those of the maxillaries increasing- in length 

 posteriorly, forming- a continuous series. 



Only one species is known, forming the transition from Tropidonotus to the true fresh- 

 water snakes. Cantor says that it is very fierce, and prepares to attack by raising the head 

 3 or 4 inches vertically from the ground, and that it has the power of flattening and laterally 

 expanding the skin of the anterior part of the body, like Naja, but in a much slighter degree. 

 Frogs and fishes form its food. 



