ORDER OPHIDIA. . 277 



tisiphone, because they have no fossets behind the 

 nostrils. 



Sometimes the plates of the base of the tail are 

 entire ; they are 



The Trimeresuri, Lacep., 



Which have large plates on the head, a part of their 

 plates double, and the others simple.* 

 Others, 



The Oplocephali, Cuv., 



Have large plates upon the head, and all the subcau- 

 dal plates simple, f 

 Others again. 



The AcANTHOPHis of Daudin, or the Ophrias of 



Merrem, 



Have plates on the front of the cranium and the 

 head. Their tail terminates in a crook. Almost 

 all its plates are simple. Sometimes it has some 

 double ones under its extremity.^ 



* Tnmeresure Petite Tete, Lacep. An. Mus. IV. Ivi. 1 . 



-j- The species are new. 



X Acanthophis Cerastinus, Daud. V. Ixxvii., and Merrem ; Beytr., II. ix., 

 or Boa Palbebrosa, Sh. ; Ac. Broronii, Leach, Zool. Miscell. I. iii., the 

 most venomous reptile iu the environs of Port Jackson. 



