118 



SNAKES OF CEYLON 



and the whoJe period would be about fifty days. Again, in 

 ►Shillong, on August 18, I had eggs brought to me which 

 contained embryos. Twenty days later, viz., on September 2, 

 I extracted an embryo measuring 3J inches, or about half the 

 length of a hatchling. Allowing 1 inch for the embryo 

 when the eggs were discharged, the growth was 2 J inches in 

 twenty-five days, and the total period of incubation would 

 work out at about fifty days. (Fig. 25.) 



Fig. 25. — Showing the development of Amphiesma stolata. 



A. Coiled in egg. 



B, C, D. The same after extraction. 

 E. The head of same enlarged. 



(b) The Hatchling : The embryos liberate themselves from 

 the egg by means of an osseous structure, which is specially 

 developed for this purpose, and is very soon — a day or two — 

 shed after its function has been fulfilled. This is called the 

 foetal tooth or egg tooth, and is developed in the premaxillary 

 bone. Unlike the ordinary teeth, which are already developed 

 at this stage of life, it is flattened, and its cutting edge lies 

 horizontally, projecting forward beneath the arch in the front 

 of the mouth, which is formed to admit of the protrusion of 

 the tongue when the jaws are closed. With this instrument 

 the embryo makes one or many incisions, which penetrate the 

 egg shell, but even when it has established an adequate means 

 of exit, the little snake seems loathe to abandon its cradle, for 



