606 OPHIDIA COLUBRIDAE CHAP. 



smooth black or brown and highly iridescent scales, hence the 

 generic name. The ventral scales are white and transversely 

 enlarged as in the majority of snakes. The tail is short, but 

 not stunted, measuring about 4 inches in full-grown specimens 

 of a total length of 3 feet. 



Fam. 7. Colubridae. This family comprises those snakes 

 (about nine -tenths of all recent species) which combine the 

 following characters : ectopterygoids are present : the squamosals 

 are loosely attached to the skull, and carry the quadrates, which 

 are not reached by the pterygoids : the prefrontals are not in 

 contact with the nasals : the maxillaries are horizontal and form 

 the greater portion of the upper jaws : the mandibles lack the 

 coronoid process or element : both jaws are toothed. 



The best arrangement of this enormous cosmopolitan family 

 with terrestrial, arboreal, and aquatic forms, is that by Boulenger, 

 who, adopting Dumeril's terms, has divided them into three 

 parallel series. 



A. Aglypha. All the teeth are solid and not grooved. 



B. Opisthoglypha. One or more of the posterior maxillary 

 teeth are grooved. 



C. Proteroylyplia. The anterior maxillary teeth are grooved 

 or " perforated." 



The Aglypha are harmless, non-poisonous. Most of the 

 Opisthoglypha are poisonous, although few of them are danger- 

 ously so. The Proteroglypha, which comprise the " Cobras " and 

 their allies, are deadly poisonous. 



Series A. AGLYPHA. 



Sub-Fam. 1. Acrochordinae. The postfrontal bones, besides 

 bordering the orbits posteriorly, are extended forwards so as to 

 form the upper border of the orbits, separating the latter from 

 the f rentals. The few genera and species of this sub -family 

 are mostly aquatic, inhabiting rivers, or estuaries with brackish 

 water, and they have been known to swim far out into the sea. 

 The body is covered with small, frequently granular scales ; in the 

 typically aquatic forms the body is slightly compressed laterally, 

 and the ventral scales are scarcely larger than the others. Most 

 of these ugly snakes inhabit the rivers of coasts of South -Eastern 

 Asia and Papuasia ; one, Stoliczkaia, is found in the Khasia Hills 



