220 OPHIDIANS. DEIRODON. 



I shall first describe the dental peculiarities of the true Serpents, 

 and afterwards notice those of the AmphishcBno! in connexion with 

 the teeth of the Anguis and other serpentiform genera, which lead by 

 a series of close transitions to the Saurian order. 



All true serpents subsist on animal matter and swallow their 

 food whole, whether they prey on living animals, as is the case in 

 almost every species, or feed on the eggs of birds as in the Deirodon 

 scaler, O., {Coluber scaber, Linn.) 



With the exception of this and some congeneric species, in which 

 the teeth of the ordinary bones of the mouth are so minute as to have 

 been deemed wanting, the maxillary and premandibular bones in all 

 true Ophidians are formidably armed with sharp-pointed teeth ; there 

 is on each side the palate a row of similar teeth supported by the 

 palatine and pterygoid bones ; in the great Pythons and some species 

 of Boa the intermaxillary bone also supports teeth. 



All the teeth, whatever be their position, present a simple conical 

 form, the cone being long, slender and terminated by an acute apex, 

 and the tooth is either straight, or, more commonly, bent a little 

 beyond the base, or simply recurved, or with a slight sigmoid 

 inflection. The teeth are thus adapted for piercing, tearing, and 

 holding, and not for dividing or bruising. In some species certain 

 teeth are traversed by a longitudinal groove for conveying an acrid 

 saliva into the wounds which they inflict : in others two or more teeth 

 are longitudinally perforated for transmitting venom ; such teeth are 

 called 'poison-fangs' and are always confined to the superior maxillaries, 

 and are generally placed near the anterior extremity of those bones. 



The serpents in which the teeth are all simple and solid, when the 

 pulp which occupies the basal cavity is calcified, will be first noticed. 



92. Deirodon. — In the genus Deirodon{l) the teeth of the ordinary 

 bones of the mouth are so small as to be scarcely perceptible, and they 

 appear to be soon lost, so that it has been described as edentulous. 

 An acquaintance with the habits and food of this species has shown 

 how admirably this apparent defect is adapted to its well-being. Its 

 business is to restrain the undue increase of the smaller birds by 



(1) Genus Anodon of Dr. A. Smith by whom the habits of the typical species have been well 

 elucidated. The name anodon had been previously applied to a genus of Bivalves 



