COLUBRINAE 6ll 



rivers have nearly dried up, these snakes collect in great 

 quantities in the remaining stagnant and muddy pools, and 

 as the stock of suitable fish gets exhausted, are often reduced to 

 a deplorably emaciated condition. By the month of August 

 they have become so thoroughly aquatic that they cannot be 

 kept alive in dry surroundings for twenty-four hours. Those 

 which I collected generally died, apparently from some kind of 

 cutaneous suffocation, during the night following their capture. 

 Taken under other conditions they are very easily kept and 

 tamed. 



[ once caught a Viperine Snake in a ditch whilst it was 

 swallowing an eel of nearly its own length. Both were separated, 

 and then put into a small bag together with other creatures, 

 and no more attention was paid to them for several hours. 

 When I opened the bag again, the snake, undisturbed by my 

 incessant walking about, was again busily engaged in trying to 

 get outside that same eel ! 



T. sirtalis (Fig. 160) is one of the almost endless varieties of 

 what is now known by the name T. ordinatus, of North and 

 Central America. 



T. tesselatus is closely allied to T. viperinus, which it represents 

 in South Germany, Italy, South-Eastern Europe, and Asia ; but 

 the scales form only nineteen rows, and the fourth, or fourth and 

 fifth labials, border the eye. The usual colour is olive-grey with 

 dark little spots, and with a dark chevron-shaped band behind 

 the occiput. The lower parts are yellow or red checkered with 

 black, hence the specific name. 



Zamenis. The maxillary teeth are not closely packed ; they 

 increase slightly in size backwards, and the last two are often a 

 little larger and separated from the rest by a diastema. The 

 mandibular teeth rather decrease in size from before backwards, 

 inversely with the upper teeth. The scales are smooth with 

 apical pits ; the sub-caudals form two rows. The eye is lar^e, 

 and has a round pupil. The range of this genus, with about 

 thirty species, extends over the whole of the Periarctic region. 



Z. (Ptyas) mucosus (Fig. 161), the Rat Snake of India, extending 

 from Transcaspia to Java, is a very common species, often seen in 

 menageries. Its general colour is brown above, often with black 

 cross-bands on the hinder part of the body and tail. The under 

 parts are yellowish. The fourth and fifth labials border the eye. 



