XIII COLUBRINAE 6 1 I 



rivers have nearly dried \ip, Lho«e snakes collect in ui'cat 

 C[iiantities in the remaining stagnant and miuldy pools, and 

 as the stock (if 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. Tliose 

 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. 



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

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

 and tlien i»ut into a small ba<'- tou'ether with other creatures, 

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

 When I opened the liag again, the snake, undisturlied by my 

 incessant walking about, was again busily engaged in trying to 

 wet outside that same eel ! 



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

 what is now known l»y tlie 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 ; l)ut 

 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 backw^ards, and the last two are often a 

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

 mandibular teeth rather decrease in sjze from before backwartls, 

 inversely with the upper teeth. The scales are smooth with 

 apical pits ; the sub-caudals form two rows. The eye is large, 

 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 Eat 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-bauds on the hinder part of the body and tail. Tbe under 

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



