Mr. G. A. Boulenger on the Genus Pseudoxyrliopus. 313 



B. Scales in 21 rows ; frontal a little longer 



than broad ; two labials entering the eye. 



a. Rostral just visible from above ; ventrals 



155 ; subcaudals 35 P. heterurus, Jan. 



b. Portion of rostral visible from above at 



least half as long as its distance fi-om 

 the frontal ; ventrals 142 ; subcaudals 

 45^7 r. quinquelineatus, Gthr. 



C. Scales in 19 rows; frontal longer than 



broad; portion of rostral visible from 

 above half as long as its distance from the 

 frontal ; two labials entering the eye ; 

 ventrals 137-146 ; subcaudals 40-47 .... P. imerince, Gthr. 



D. Scales in 17 rows ; frontal a little longer 



than broad ; three labials entering the 



eye ; ventrals 102 ; subcaudals 42 P. punctatus, Ptrs. 



All agree in the following points : — Supraocular not more 

 than half the width of the frontal ; loreal longer than deep ; 

 one pree- and two postoculars ; temporals 1 + 2 ; anal divided. 



List of the Species. 



1. Pseudoxyrhopus microps. 



Pseudoxyrliopus microps, Giinther, Ann. & Mag. Nat. Hist. (5) vii. 

 1881, p. 359, fig. 



Betsileo. 



2. Pseudoxyrhopus heterurus. 



Homahceplialus heterurus, Jan, Arch. Zool. Anat. Phys. ii. 1803, p. 280, 

 and Icon. Ophid. xvii. pi. iv. fig. 2 (1800). 



Madagascar. 



3. Pseudoxyrhopus quinquelineatus. 



Liophis quinquelineatus, Giinther, Ann. & Mag. Nat. Hist. (5) vii. 1881, 

 p. 359, fig. 



Betsileo. 



4. Pseudoxyrhopus imerince. 



Cvronella microps, Boulenger, Ann. & Mag. Nat. Hist. (0) i. 1888, 



p. 104, pi. V. fig. 4. 

 Liophis imei-incs, Giinther, Ann. & Mag. Nat. Hist. (0) v. 1890, p. 71. 



Iraerina. 



L. imerirue is the adult of the previously described G. 

 microps^ which name, howeverj is preoccupied by Pseudoxy- 

 rhopus microps^ Gthr. 



