( xiii ) 



A hilly country like Ceylon is to be regarded from the 

 zoo-geographical point of view as an archipelago. Many 

 snakes inhabiting upland regions have a very restricted 

 habitat, neither ascending nor descending beyond certain 

 limits. Many of the elevated ranges and peaks whose lower 

 slopes merge into the low-country are just as effectually isolated 

 as if they were surrounded by the sea, and thus form zoological 

 islands. The field naturalist from this remark will see how 

 important it is to attach a record of habitat and altitude to 

 the specimens he collects. It would be natural to suppose 

 tliat the denizens of the low-country are distributed throughout 

 that area, seeing that there are no natural barriers to obstruct 

 their wanderings. As far as is known, however, one snake, 

 viz., the saw-scaled viper (Echis carinatus), occurs only in the 

 northern part of the Island, and it is possible, when more 

 records are available, that other species may similarly be 

 found to be restricted in their habitat, dependent on rainfall, 

 geological, and other conditions. From available records 

 many of the hill species appear to be very local, apart from 

 inhabiting a restricted belt of elevation. 1 think it extremely 

 probable that many more hill snakes remain to be discovered 

 in peaks and ranges that have up to now escaped special 

 exploration. How httle the Island has been explored is 

 illustrated by my having discovered during my two months' 

 visit to Ceylon two new species (viz., Bhinophis drummond-hayi 

 and' B. porrectus), a specimen of the Indian Krait {Bu7igarus 

 casruleus), only recorded three times before, and a specimen of 

 the gamma tree snake {Dipsadomorphus trigonatus), the 

 occurrence of which in Ceylon has been doubted, since tlie 

 only mention of it is by Ferguson in 1877 ! I am extremely 

 indebted to Mr. H. M. Drummond-Hay for placing his 

 collection at my disposal and for much information. I had 

 the pleasure of paying him a short visit, which proved to be 

 quite an event in my life. I found his bungalow a veritable 

 museum, stocked with specimens of every kind. He has 

 devoted his attention more possibly to the snakes of Ceylon 

 than to any other branch of Natural History, and I had the 

 rare opportunity of examining many hundreds of specimens 

 collected by him. Mr. Drummond-Hay is one of those rare 



