12 



and skilful manipulation in the Elapidce, but in the vipers 

 the arrangement is on a larger scale and much easier of 

 demonstration. 



If we now dissect away the soft parts and expose the 

 maxillary, we shall see a great modification in its form com- 

 pared with the normal type. It barely reaches as far back 

 as the hinder part of the orbit, its shortness being compen- 

 sated by increased length of the ectopterygoid. A short 

 tooth is found at its hinder part, but this is rarely percep- 

 tible until dissected down to, and appears to be rudimentary. 

 The shape of the maxillary resembles that of a comma »• 

 the open space protected by the thin curved part being 

 occupied by the matrix of the fang ; the thick part in front 

 bears the fang. This part of the bone is thick and wide, and 

 it bears, side by side, depressions for two fangs ; one, the 

 outer socket, is generally occupied by the fang in use, the 

 other by the fang in course of growth. When the fang in use 

 has only recently set it may be found to occupy the inner 

 socket, whilst the outer socket, from which the old fang has 

 just fallen is vacant, and remains so until the new fanw has 

 worked its way outwards. Sometimes these two fan^s are 

 found perfect at the same time, then one of them, generally 

 the outer or old fang, will be loose. This occurs at the time 

 of casting the skin, and I have several times removed the old 

 fangs easily with the finger and thumb or a small forceps. 



The fang is slightly curved backwards and inserted at an 

 angle so as to form a hook in the jaw. It is in shape like 

 a short elephant-tusk and does not exceed 28-hundredths 

 of an inch in the longest specimen I have Seen. In struc- 

 ture it diifers from other teeth in having, when fixed, two 

 orifices communicating with the interior. The pulp cavity 

 is atrophied, and in front of it there is a complete canal 

 Both orifices of this canal are in front, the upper close to 

 and forming part of the base, the lower at a distance from 



