FROM OREGON AND THE WESTERN COAST OF AFRICA. 305 



hexagonal scales, with margins more or less rounded posteriorly ; the plates upon the 

 under part of the tail are bifid. 



Color.— Re^d olive colored above, lighter upon the sides ; the posterior margins of 

 the labial plates black ; posterior margins of inferior labials also black ; neck, upper 

 part and sides of body green, the scales upon the posterior part of the body bordered 

 with black ; abdomen greenish, without spots or blotches ; tail greenish olive, many 

 of the scales bordered with black. 



Dimensions.— Length of head 1 inch 4 lines; greatest breadth 9 lines; length of 

 body 3 feet 1 1 inches 2| lines ; length of tail 1 foot 5 inches 7 lines ; total length 5 

 feet 7 inches 2 lines; greatest circumferance 2 inches 8 lines. 



I have named this serpent after my friend Ogden Hammond, Esq., of Charleston, 

 South Carolina. 



Dimensions of a larger specimen. — Length of head 1 inch 6J lines ; greatest 

 breadth 11 lines; breadth between the orbits posteriorly 9 lines; length of body 4 

 feet 6i inches; of tail 1 foot 5 inches 9 lines; total length 6 feet 1 inch 9J lines 

 greatest circumference 3 inches. Abdominal scuta 225; 112 pairs of subcaudal 

 plates. 



Habitat. — Liberia, Western Africa. Two specimens in the Museum of the 

 Academy, presented by Dr. Goheen. 



Remarks. — The dentition of this animal is very remarkable, no serpent with which 

 I am acquainted having a single immovable perforated fang on each side of the 

 anterior portion of the upper jaw. It is well known to Herpetologists that, although 

 in Viper a, Naja, and other genera of venomous snakes, the exterior row of teeth is 

 wanting, the poisonous fangs in certain serpents have behind them a number of 

 smaller grooved teeth. This condition exists, according to Professor Owen, in all the 

 family of marine serpents, four such being found in Hydrophis striata, and five in 

 Hydrophis schistosa. This is the case also in Bungarus, a land serpent, and in 

 Hamadryas, a genus of poisonous tree snakes* in India, established by Dr. Cantor.f 

 In our own venomous serpents, Elaps, Trigonocephalus, and Crotalus, the exterior 

 row of teeth is wanting. In this respect they resemble Dinophis, but the fang in the 

 latter genus is, as above stated, quite immovable. In one of the specimens a 

 movable perforated fang was observed on the right side behind the other immovable 

 one. 



Dr. Edward Whitaker Gray, in the Philosophical Transactions of London for ' 

 1789, makes some interesting observations on the "class of animals called by 

 Linnaeus, amphibia : particularly on the means of distinguishing those serpents which 



* These poisonous tree snakes are probably more numerous in the East than is generally supposed. Dr. 

 Ruschenberger informs me that in Siam he observed a large green tree snake, which was said by the natives to 

 be very venomous. 



t Proceedings of the Zoological Society of London, 1838, p. 72. 



77 



