SNAKES OF CEYLON. 319 



(/) Hissing : Dr. Annandale says they do not hiss, but 

 utter a low gurgling note. 



(g) Sloughing : Desquamation occurs at intervals as in 

 the case of land snakes, but the slough is cast in fragments. 



Food. — As far as is known they are entirely piscivorous. 

 The fishes usually selected are those with slender elongate 

 bodies. Dr. Annandale mentions Silurids (Cat fishes), and 

 Gunther the Silurid fish, Apogon. I have extracted fish from 

 some, which Dr. Henderson identified as Mursenids (eels). 

 An element of doubt lay between the species Ophichthys boro. 

 or 0. orientalis. Many of these fish have very strong spines 

 as noted by Gunther, and Dr. Annandale says that the spines 

 are frequently discharged through the tissues . They penetrate 

 the walls of the stomachs, and work their way through the 

 tissues between the ribs, and are finally expelled, without 

 causing any serious mischief to the snake. This is a curious 

 adaptation, for the danger of such spines wounding the 

 intestine must be great. 



Breeding. — (a) The Sexes : There is nothing very special 

 to remark. Both appear to grow to similar lengths. In the 

 female the body is deeper posteriorly, and especially so when 

 gravid. In the males a bilateral swelling along the base 

 of the tail corresponds to the clasper tubes. In some I have 

 found the male genitalia bifid, in others not. The genitalia, 

 as in land snakes, are extruded in intra -maternal life until 

 shortly before birth, but they are ensheathed some appre- 

 ciable time before birth. The tubercles and keels on the 

 costals and ventrals are usually more pronounced in males, 

 and grow stronger with advancing years.* 



(b) Method of Reproduction : All those whose breeding 

 habits are known are viviparous. 



(c) Season : The breeding season probably extends over 

 several months of the year, but available records are too 

 limited to elucidate this point. 



* In many spirit specimens the character of the keels and tubercles 

 on the scales are difficult to discern, but I have satisfied myself that 

 these are distinct and constant in both sexes from the earliest age, even, 

 in fact, before birth. 



