Mr. G. A. Boulenger on the Genus Pseudoxyrhopus. 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 from 
the frontal ; ventrals 142 ; subcaudals 
45-47 P. 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 162 ; 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 prae- and two postoculars ; temporals 1 + 2 ; anal divided. 
List of the Species . 
1. Pseudoxyrhopus microps. 
Pseudoxyrhopus microps , Gunther, Ann. & Mag. Nat. Hist. (5) vii. 
1881, p. 359, fig. 
Betsileo. 
2. Pseudoxyrhopus heterurus . 
Homcilocephalus heterurus , Jan, Arch. Zool. Anat. Phys. ii. 1863, p. 286, 
and Icon. Ophid. xvii. pi. iv. fig. 2 (1866), 
Madagascar. 
3. Pseudoxyrhopus quinquelineatus. 
Liophis quinquelineatus , Gunther, Ann. & Mag. Nat. Hist. (5) vii. 1881, 
p. 359, fig. 
Betsileo. 
4. Pseudoxyrhopus imerince. 
Coronellu microps , Boulenger, Ann. & Mag. Nat. Hist. (6) i. 1888, 
p. 104, pi. v. fig. 4. 
Liophis imerince , Gunther, Ann. & Mag. Nat. Hist. (6) v. 1890, p. 71. 
Imerina. 
L. imerince is the adult of the previously described G. 
microps , which name, however, is preoccupied by Pseudoxy- 
rhopus microps, Gthr. 
