150 ON THE BATRACHIA AND REPTILIA OF COSTA RICA. 



118. Bothriechis'nigroviridis, Peters, 1. c; Cope, 1. c; Monatsber. K. Preuss. Akademie, 1859, 



p. 218; Cope, Pr. A. N. Sci. Phila. 1859, p. 345; Thamnocenchris, Salvin. 



This genus is, like the last, confined to the great forests of Central America 

 and the northwest of South America. Species have been found further north than 

 those of Teleuraspis. Like the latter they inhabit trees, filling the place in America 

 of the species of the East Indies which belong to the Bothropes, and of the tree- 

 vipers of Africa, Athens, Cope. All the species of these different groups are of 

 green colors, in contradistinction to those of terrestrial habits, which are of various 

 shades of brown. This is evidently related to their convenience in the struggle 

 for existence in the localities in question. 



From an elevated point on the Pico Blanco. Mr. Gabb states that it occurs 

 in the central valley also, from which it has been brought by Dr. Van Patten. 



119. BoTHRiEOHis LATERALIS, Peters, Monatsb. K. Preuss. Acad. 1862, p. 6Y4 ; Bothrops bilinea- 



tus, Pet., 1. c. 1859, p. 218 ; ? Bothrops Mcolor, Bocourt, Ann. des Sci. Nat. 1868, p. 201. 

 Costa Rica. 



120. BoTHRiOPSis AFEiNis, Bocourt, Ann. Sci. Nat. 1868, p 201; Teleuraspis mexicanus, Cope, 



Pr. A. N. S. 1859, p. 339 ; Bothriechis do., Cope, 1. c. 1860, p. 345; nee Atropus mexicanus, 



D. B. 



Mexico, as far north as Tuxpan, and Central America to Costa Rica. 



Superciliary shields very narrow ; no small scales surrounding rostral. Scales 



in 23 (" 25") rows, three inferior smooth ; small scales on canthus, four rows below 



eye; rostral broad as high; nine superior labials, fourth largest. Twenty-two 



dorsal rhombs. 



The species of this genus are all of terrestrial habits, and approach in this 

 respect the Ancistrodontes. They have a more extended range than any of the 

 preceding, occurring from the upper or Peruvian Amazon to northern Mexico. 

 They are very venomous, but not so much dreaded as the true Bothropes of the 

 same regions, which attain a larger size. 



121. BOTHRIOPSIS PROBOSCIDEUS, Sp. nOV. 



A rather small species of sombre colors, allied to the B. hrachystoma. Scales 

 in twenty-three series, all carinate, the inferior but slightly ; those of the top of 

 the head and muzzle not very different in size, also keeled. Superciliary plates 

 each a broad oval, the two separated by five rows of scales, of which the external 

 on each side follows the inner border of the plate. A narrow shield on each side 

 of the end of the muzzle which is bent up at its middle, lying against the posterior 

 side of the rostral plate, and in contact with its fellow, the extremities of the two 

 having a bilobed outline. Rostral plate three times as high as wide, lying against 



