NATURAL SCIENCES OF PHILADELPHIA. 107 



Thrasops occidextalis, Almtulla occidentalis Gunther, Proc. Zool. Soc. Lond. 

 1859, 412. 

 From Guayaquil, from Messrs. Detruger and Reeve. 



OXYBELIS ACUMINATUS, Wicd. 



Guayaquil, 6687. 



Olisthknes coronatus, Scytale coronaiiim, Dum. Bibr. Gthr. 



OxYRHOPCs SEB.E, Dum. Bibr. vii, 1056. 



From the valley of Quito. The stomach contained a Lioceijhalus. 



Leptognathus bdcephaltjs Cope, Dipsas Scbleg. Dipsadomorus indicus Dum. 

 Bibr. Dipsadomorus hucephalus Jan. Leptognathus indicus Gunther. Tab. 

 Seba, xliii, 4-5. 



This species is no doubt the type of Laurenti's genus Dipsas, as I have 

 pointed out, (Proc. Acad. 1860) but by the rule of exclusion, as -Leptognathus 

 was first taken from it, the remaining species, to which Dum^ril and Bibron 

 applied the name Triglyphodon, should retain the original name. 



Fine specimen ; Napo or Maranon. 



As the species in the Academy are not embraced in the Erpetologie G6nerale 

 and other works, I give a synopsis of those known to me, six of them not 

 described in any general work. The species not embraced in the Equador col- 

 lections are described at the end of the catalogue. I have been aided in this 

 by Jan's Elenco serpentium. 



Group L Dorsal scales smooth, a larger vertebral 



series ; anterior genials very short ; two pairs of 



inferior labials in contact in advance of the genials. 



{Dipsadomorus D. B. Jan.) 



Scales in 13 rows ; a large preocular ; above and below liver 



brown, with broad lighter cross bars, which terminate 



in a bright yellow spot on the edges of the gastrosteges ; 



six genials, with lateral plates behind bccephala. 



Scales in fifteen rows ; no preocular ; four genials ; dark 

 brown, with darker cross-bars ; below yellow with lat- 

 eral dark spots tariegata. 



Group n. Scales smooth, vertebral series larger ; 

 anterior genials small, preceded by one pair of 

 labials ; 



A. Loreal plate not reaching the orbit. 

 Two preoculars, two postoculars, scales in thirteen rows ; 

 vertebral plates reaching occipital ; nine upper labials ; 

 chestnut brown, with black yellow-edged discs on the 

 sides which become confluent into broad cross rings an- 

 teriorly, separated by yellow ; head black with yellow 



collar and cross band on muzzle catesbyi. 



«a. Loreal plate entering the orbit. 



0. Two postoculars. 



Thirteen series of scales, (ten) eleven superior labials, one 



preocular, twelve inferiors, six genials, without laterals, 



vertebrals not reaching occipitals ; light, a series of 



broad rounded, brown light edged dorsal spots, just 



reaching gastrosteges ; belly unspotted pavonina. 



Fifteen series scales, nine superior labials, no preoculars, 

 eleven inferiors, four genials, no lateral genials, verte- 

 brals not reaching occipitals ; much compressed; yellow 

 with broad brown entire annuli ; nape and temples and 

 spots on muzzle yellow articulata. 



1868.] 



