NATURAL SCIENCES OF PHILADELPHIA. 135 



on the line of the second and third rows of scales, extends throughout the 

 posterior five-sixths the length. A dark shade through eye. Middle half of 

 gastrosteges yellow. 



From Yucatan; A. Schott, of the Comision Cientifica. 



I had enumerated this as the M. b i 1 i n e a t u s of Schlegel (Pr. A. N. S. 

 1866, 127), but an examination of Jan's beautiful figure enables me to correct 

 the error. 



LEPTOGNATHUS Dum. Bibr. 

 Giinther, Jan. 



A review of the species of this interesting genus has been already given. I 

 give here references to all the species, and descriptions of some new ones not 

 contained in the Williams College collection. 

 Leptognathds bucephala Cope, iShaw, see Catalogue. 



Leptognathus variegatds Dum. Bibron, Erpet. Gen. vii, p. 477. Dipsadomo- 

 rus Jan. 



From Surinam. No specimen of this species has fallen under my observa- 

 tion. 

 Leptognathds catesbyi Giinther, Weigel. See Catalogue. 



Leptognathus pavonina Dum. Bibr. Schleg., Erpet. Gen. vii, 474. 

 Guiana. 



Leptognathus articulata Cope, sp. nov. "i)//?.';?.? irms Dum. Bibr.," Cope, 

 Proc. A. N. Sci. Philada. 1860. Not of Dum. Bibr. 



The most slender, compressed species of the genus. Muzzle very short ; 

 frontal plate hexagonal, sides converging, length equal width ; occipitals 

 broad and squarely truncate behind, not reached \>j the vertebral series of 

 plates. Fourth and fifth superior labials entering orbit, sixth nearly excluded 

 by the long lower postocular. Temporals two — three, with one inferior addi- 

 tional in contact with postocular. Sixth and seventh inferior labials con- 

 nected by one transverse plate. 



The brown annuli are wider anteriorly than posteriorly ; the second covers 

 lOj rows of scales, the seventeenth, just in front of the vent, Qh- The yellow 

 annuli are of nearly uniform width — ^\ scales, — and without spots above or 

 below. Top of head, sides, and upper labials in front of eye, all the lower 

 labials, brown; rest of head with numerous short lines on the muzzle, yellow 

 or white. 



Gastrosteges 215; anal 1; urosteges 135. Total length 26-5 in. ; of tail 

 8-75 in. ; of gape 6 in. 



From Veraguas, Costa Rica ; sent to the Academy by R. W. Mitchell. 



Leptognathus mikanii Giinther, Schlegel. Anholodon mikanii Dum. Bibr. 

 vii, 1165. 



Eastern Brazil. 



Body not elongate, but much compressed. Head less elevated, and with 

 flatter muzzle than in the last. 



Loreal square ; frontal nearly equally hexagonal, with straight sides ; occi- 

 pitals elongate, rounded posteriorly. Third and fourth labials bounding or- 

 bits, the anterior little higher than long, posterior two much longer than 

 high. Temporals 1 | 2, all longer than high, anterior in contact with both 

 postoculars. 



Dorsal cross-bands two scales wide, four scales apart, with zig-zag outlines 

 from never crossing a scale. Posteriorly their extremities are broken oif into 

 a lateral series of spots. Belly with a series of elongate blotches on each 

 side, which alternate with the lateral spots ; dusted with brown medially. 

 Top of head dark brown, with five darker light-edged spots ; one on the junc- 

 tion of prefrontals with frontal, on one outer posterior angle of latter, and 

 one on each occipital plate. Labial plates all reddish- brown margined. 



1868,] 



