ABOMA. 



63 



length of the back, and variable spots on the sides ; these are 

 generally dark, with a whitish semi-lunar mark. This formidable 

 RejDtile has all the habits of its congeners ; it is found in the 

 marshy swamps of 

 trop)ical America, 

 and near the rivers, 

 where it lies in wait 

 for its prey. 



The Boas, jjro- 

 perly so called, 

 have the scales 

 smooth ; labial 

 shields smooth, not 

 pitted ; the body 

 compressed, taper- 

 ing to the tail, 

 wliich is long and 

 prehensile ; the 

 head is compara- 

 tively small, being 

 enlarged behind, 

 and contracted 

 towards the muzzle, 

 which is rather 

 short. The crown 

 is covered with 

 scales; the nostrils 

 lateral, between two 

 plates. Four spe- 

 cies of this genus 

 are recognised by naturalists, all of which have been described by 

 travellers as the true Boiguacu, or Boa-constrictor of Linnteus. 

 This species has the scaly circle of the orbit separated from the 

 upper labial plates by one or two series of scales. A large chain 

 consisting of blackish hexagonal spots, alternating pale oval stains, 

 notched and jagged, extending the whole length of the back, and 

 forming a very elegant design. This species seems to be strictly 

 confined to tropical America. Humboldt found it in Guiana, and the 



Fi;^. 1-5. — Alioma {EjAcrafes cenc/iria). 



