ON THE BATRACHIA AND REPTILIA OF COSTA RICA. 149 



long ago by Beauvois, and adopted by Gray and others, that is the' Ancistrodon of 

 North America and Mexico, but most of the genera have only been recognized 

 within a recent period. In March, -1859, Prof. Peters distinguished a second genus 

 of the group, and towards the close of the same year the writer named a third. 

 Prof. Peters named another genus, which may be retained, though in a sense quite 

 different from that in which it was originally intended. I allude to Bothriopsis, 

 first defined by the four small scuta on the top of the muzzle of one of the species, 

 a character not worthy of such a valuation. The characters adopted will be seen 

 below. All the known species are found between north Mexico and Peru. 



I. Head scaled above. 



a. Body compressed, tail prehensile (arboreal). 

 A series of horn-like scales above the eye, outside of the superciliary shield. 



Teleuraspis. 

 Superciliary reaching to the edge of the eye opening ; no horns. Bothriechis. 



aa. Body cylindric, tail straight {terrestrial). 

 Nasal plate one. Porthidium. 



Nasal plates two. Bothriopsis. 



II. Head with nine plates above. 



Body cylindric; two nasals. Ancistrodon. 



in. Teleurapsis schlegelii, Berthold, Abh. Wiss. Gottingen, 1841, iii. 13 (Trigonocephalus), 

 Cope, Pr. A. N. Sci. 1859, p. 338 ; 1860, p. 345. 



This species is abundant in eastern Costa Rica, and displays three color varie- 

 ties. All the specimens have twenty-three rows of scales, and some eight, and 

 others nine superior labials. There is no tendency to division of the urosteges. 

 From Ecuador to Costa Rica. 



Var. I, nitida, Giinther, Proc. Zool. Soc. Lond. 1859, nov. Tab. (Lachesis), 



I.e. 345, et 1868, p. 110. 

 Green with brownish-red vertical bands on each side which usually alternate ; 

 belly green and yellow varied with black, punctulate. Ecuador. 



Var. 11. Green with a series of small brown dorsal spots; below as in Var. I. 

 Var. Ill, nigroadspersus, Steindachner, Sitzungsberg. Wien. Akademie, 1870, 



May, PI. VIII. 

 Golden yellow ; lower surfaces unspotted. 



According to the observation of Mr. Gabb, this is a dangerous species, its bite 

 requiring prompt treatment to prevent a fatal result. It is distributed from the 

 coast (Old Harbor) inland to an elevation of 5-600 feet above the sea. 

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