REPTILTA. 257 



in most. The two branches of lower jaw conjoined by a cartila- 

 ginous elastic ligament. Mental furrow. 



The serpents with a large mouth capable of great expansion on de- 

 glutition, form the largest part of their order, and exhibit to us the 

 proper typus of it. Along the under jaw on each side lie a row of 

 scutes (Scuta marginalia labiiinferioris), between which two pairs of 

 mental scutes (Scuta mentalia) are situated, and again in front of 

 these two small scutes, behind the unpaired scute at the point 

 of the lower jaw (Scutum labiale medium). Between these mental 

 scutes there runs in the middle a longitudinal furrow. 



The upper jaw is formed by two upper jaw-bones and a single 

 intermaxillary bone. The upper jaw-bones are longer in the in- 

 nocuous serpents, and armed with a row of teeth, continued 

 throughout. In the poisonous serpents, on the contrary, the 

 upper jaw-bones are short, and the outer pterygoi'd bone (Os 

 pterygdideum externum) to which they are fastened, is transformed 

 into a much elongated style. 



f Venomous serpents. (Solenoglyphes, previously Tkanatophides, 

 BUM. and BIBR.) 



The venomous serpents, amongst which are some whose bite has 

 for men speedy death as a consequence, have brought an evil name 

 upon the whole order. They are, however, far less numerous than 

 the innocuous species. Even in Brasil, for instance, according to 

 the Prince of NEUWIED, the innociious species are to the venomous 

 as 38 : 5. This is the place to say something on the poison-glands 

 and poison-teeth of serpents. 



In most poisonous serpents each superior maxillary bone has 

 only a single tooth projecting from the gum, and, to succeed to 

 which, two or three others behind and above it lie upon the palate 

 with their point turned backwards. Through these teeth there 

 runs a canal which opens close to the point on the convex anterior 

 surface with a fine fissure. In some poisonous snakes the upper 

 maxillary bone has some smaller teeth in addition, which are not 

 perforated, and succeed further back to the poison-tooth. Finally, 

 there are (as was first observed by Professor REINWARDT and con- 

 firmed by the investigations of BOIE, and especially of SCHLEGEL, by 

 whom this peculiarity was published,) some serpents which have a 

 tooth behind a row of imperforate teeth which is a little longer 

 VOL. II. 17 



