36 LECTURE VII. 



accidental violence. But poisonous Serpents may 

 often be at least guessed at, though not demon- 

 strated, from the habit or general appearance of 

 the animal, most of the venomous Serpents having 

 rather large heads, covered with small scales, 

 whereas those 'which are innocent have the head 

 generally covered with large scaly plates ; but on 

 the other hand some highly venomous Serpents 

 have the head covered with large scales also ; so 

 that no absolute mark of distinction can be found 

 except the fangs. In general it may be said that 

 innocent Serpents have four rows of teeth in the 

 upper jaw ; two on the palate and the rest on each 

 side; but that poisonous Serpents have no other 

 outward or side- teeth but the fangs. 



The genera or particular sets of Serpents esta- 

 blished by some modern naturalists are pretty nu- 

 merous, and even unnecessarily so. Linnaeus on 

 the contrary established but few. His first genus 

 is that of Crotalus or Rattle Snake. Its character 

 is that beneath the body are broad scaly semi- 

 circular transverse plates or shields ; the same, to- 

 gether with some divided shields beneath the tail, 

 and the tail itself terminated by a rattle, composed 

 of many dry horny flattish organs of a peculiar 



