PITUOPHIS CATENIFER. 135 



1. PlTUOPHIS CATENIFER, B. & G. 

 (Plate VIII, figs. 1-7.) 



SPEC. CHAR. One pair of postfrontal plates ; two anteorbitals and 

 three postorbitals. Loral large. Dorsal rows of scales thirty-one 

 in number ; the external four rows smooth. Tail forming the 

 seventh of total length. Frontal black band conspicuous. Post- 

 ocular vitta of a jet black, reaching the margin of the jaw between 

 the penultimate and last labial plate. Ground color greyish-yellow. 

 A triple series of dorsal black blotches, sixty-one in number, from 

 head to origin of tail, forming a continuous chain all along the back. 

 A series of large, subcircular blotches along the middle of the 

 flanks. Middle of abdomen unicolor, with a series of black spots 

 on each side. 



SY.V. Coluber cateni/cr, BLAINV. Nouv. Ann. Mus. d'hist. nat. Ill, 1834, PI. xxvi, 

 fig. -2, 2 a, 2 b. 



Pltuophis catenifer, B. & G. Catal. N. Amer. Kept. I, 1853, 69. 



DESCR. The head is subelliptical, flattened above. The vertex 

 plate is long, nearly equilateral, except posteriorly, where it is tri- 

 angular. The supraocularies are large, dilated anteriorly, tapering 

 posteriorly. The prefrontals are large and subcircular. The rostral 

 is broad, even with the surface of the snout. The nasals are nearly 

 equal in size, and the nostril placed between them, near the edge 

 of the prefrontal. The loral is subtrapezoid, proportionally larger 

 than in the other species of the genus. There are two anteorbitals ; 

 the upper one very large ; the lower one small and situated immedi- 

 ately above the fourth labial. We observe three postorbitals of nearly 

 equal size. The temporal shields, ten to twelve in number, are slightly 

 larger than the contiguous scales. There are eight upper labials; the 

 seventh is the largest. The lower labials are twelve in number, the 

 fifth and sixth being the largest. The posterior pair of mental shields 

 is very narrow, extending beyond the sixth lower labial. 



The dorsal scales are narrow and rather acute upon their posterior 

 extremity ; they constitute thirty-one longitudinal series, the outer 

 one of which composed of scales considerably larger than the rest. 



