THE EGG-TOOTH IN THE CEYLON KRAIT. 157 
THE EGG-TOOTH IN THE CEYLON KRAIT, OR 
KARAWELLA (BUNGARUS CEYLONICUS). 
By Magsor F. Watt, I.M.S., C.M.Z.S. 
‘Ty N this Journal* some time ago Mr. E. E. Green recorded a most 
interesting discovery of Kraits (Bungarus ceylonicus) with 
eggs and hatching young. In January, 1907, visiting Peradeniya, 
I was able to examine the hatched young and three of the eggs, and 
suggested to Mr. Green opening the eggs with a view to investi- 
gating the egg-tooth. Accordingly the three eggs were incised, the 
embryos extracted, and we searched for the egg-tooth with the aid 
of a microscope, but were doomed to disappointment. I am fairly 
certain, however, that we did not examine the jaws of the two 
hatched young. At that time I had never seen the egg-tooth of 
any snake, but since have been able to do so in several species. It 
occurred to me the other day to re-examine these specimens in the 
hope of success, now that I know what to look for, and the exact 
site of this structure. Mr. Green very kindly presented me with the 
specimens, five in all, and the eggs which we had despoiled of their 
contents. I have re-examined these with the aid of a microscope, 
with the following results. In the three young extracted by us, 
which are (1) 6 measuring 52 inches, (2) 6 6% inches, and (3) ¥ 
62 inches, I failed to discover any rudiment of the foetal-tooth, 
but in the smaller of the two hatchlings, which measures 9 inches, I 
was successful. I dislodged the structure from the premaxilla, 
and viewed it under the microscope, and find it is exactly like the . 
foetal-tooth I recently alluded to in the ‘‘ Bombay Natural History 
Journal,” which I extracted from the foetus of a pit viper. It 
bears a striking resemblance in form to a duck’s head, the 
convexity of the head filling the aperture in the front of the 
mouth, through which the tongue in later life is exserted while the 
jaws remain closed. The beak-like process projects forward slightly 
beyond the snout and ends in a horizontal cutting edge, with which 
the embryo is able to effect its freedom. 
I think-it worth while drawing attention to the close resemblance 
in shape of this egg-tooth in an oviparous colubrine snake and the 
corresponding structure in the young of a viviparous viper. In the 
one case a tough membranous investment has to be opened by the 

* Part III., October, 1905. 
