COLUBRID^: 231 



put together, and is represented in all parts of the world 

 New Zealand excepted that are not too cold, as well 

 as in the seas and estuaries of the Indo-Pacific. It is 

 divided into three sections, according to the form of the 

 teeth, namely, Aglypha, Opistboglypha, and Proteroglypha. 



(a) Aglypha (Greek a privative, and y\v(f>r) = a carving 

 or groove). In the Aglypha the. maxilla is generally long, 

 and armed with numerous teeth : none of the teeth are 

 grooved, though some of them may be enlarged. All the 

 Aglyphe Colubrines are harmless ; for although they 

 possess glands which are homologous with the poison- 

 glands of venomous snakes, and the secretion of which, 

 in some species at least, when experimentally extracted 

 and injected into small animals has been observed to 

 have distinct toxic properties, they are without special 

 means of instilling the secretion into their bite. Most of 

 the Aglypha have a loreal shield (fig. 93), but some have 

 not : in most of them none of the maxillary teeth are 

 enlarged, but there are a few species in which some of 

 these teeth are almost large enough to be mistaken for 

 small poison-fangs. In any case of doubt the tooth must 

 be examined with a lens to see whether it is longitudinally 

 grooved on its anterior surface or not. There are more 

 than 700 species of harmless Colubridce : most of them 

 are land-snakes ; but a few of them are thoroughly 

 aquatic, and though the aquatic species chiefly frequent 

 rivers some of them are marine, and as the marine 

 species are found in the same seas with the venomous 

 sea-snakes they have to be carefully distinguished from 

 the latter by an examination of the teeth and tail. 



(6) Opisthoglypha (Greek oirio-Oev = behind, and 

 y\v(f>r) = groove). In the Opisthoglypha the maxilla is 

 generally long and many-toothed : one or more of the 

 posterior teeth in the maxilla are enlarged and are longi- 

 tudinally grooved on the anterior surface, the groove 

 being a very open one (fig. 98, gr.). 



As the Opisthoglyphe Colubrines possess a gland that 

 is homologous with the poison-gland of the venomous 



