1130 



REPORT OF NATIONAL MUSEUM, 1898. 



together. The species of Cerastes are mostly dwellers in the deserts 

 of Africa, Arabia, aud Persia, and, like other desert forms, they are of 

 pale colors. They have also horuy i)rocesses, chiefly from the super- 

 ciliary region, agreeing in this respect also with the spiny character 

 of many desert reptiles and plants. The species of Cerastes are of 

 small size, and are very poisonous. The species of Vipera are not 

 numerous, aud are distributed in Europe and western and northern 

 Asia. The V. herus Limueus is the common viper of northern Euroi^e, 

 aud the T. aspis is the as^) of Mediterranean countries. The 1". ammo- 

 (lytes, or sand viper, of the latter region has a considerable production 

 of the rostral plate, so as to simulate a tactile organ. 



The African tree vipers belong to the genus Atheris. They are of 

 rather small size and of bright green and yellow colors, so as to be 

 readily concealed in foilage. Their tails are especially prehensile, liiie 

 those of the Boid;e. Four species are known. 



CEOTALID.E. 



In the Crotalid.e we have the highest efficiency of the venom appa- 

 ratus, and therefore the most specialized type of snake structure. The 

 species are predominatingly American, but a number are found in the 

 Paleotropical region, a distribution which is almost unparalleled among 

 vertebrates. The genera are distributed as follows. None are found 

 in the Australian or Ethiopian realms: 



Paleotropical. 



Palearctlc. 



Nearctic. 



Xeotropical. 



Ethiopian. 



Lachesi.s 



Peltopelor . . 



Calloselasma 



Trigonoceplialus . 



Lachesis 



Bothriopsis. 

 Botliriecliia . 

 Teleniaspis . 

 Ophryacus.. 



AncislriMlon . 



Sistriiriis 



Crotalns Crotaln.s . 



Of the above genera, Lachesis embraces the larger number of species, 

 and they occur in the Neotropical region everywhere, as well as in 

 India and Indo-lVlalaysia. Two especially dangerous species occur in 

 America — the L. atrox, of the mainland, and the L. lanceolatus (Fer de 

 Lance) of some of the southern islands of the West Indies. Some of 

 the species are more or less arboreal, as L. hieoJor, of Brazil, and are 

 of green colors, while those which live on the ground are of brown 

 hues. The Indian species are largely green in coloration. In Ophrya- 

 cus and Teleuraspis we have species with tegumentary processes above 

 the eyes. 



The Teleuraspis schlegelii of Central America is an arboreal form, 

 which is often found wound around the stems in the center of banana 

 bunches. In handling the bunches men are frequently fatally bitten. 

 The apecies of Bothriechis are also arboreal, and those of Bothriopsis 



