INKOCUOUS SEEPENTS. 
173 
the orbit is formed, as in other Ophidians, above by the 
middle frontals ; and the under part of the tail is furnished 
with simple plates. The genus is more especially proper 
to tropical America. Those of the ancient world, are of 
small size, and of dissimilar forms. 
1. Boa Constrictoe. — A terrestrial species of a size 
between 9 and 12 feet. Very distinguishable by the small 
smooth scales, which cover the body and the whole head, 
and are arranged in 67 rows, by its reddish tint relieved 
by a design composed of broad oval spots, of interlacing 
bands, and rays of a reddish brown. Form very powerful ; 
tail short ; head heart-shaped. S. 243 + 58. Inhabits 
the forests of intertropical America, where it suspends 
itself to the branches of trees, to possess itself of the small 
mammifera on which it feeds. 
2. Boa Murina. — The largest of known serpents. 
Nostrils vertical, approximated to the end of the muzzle ; 
that part and the lips covered wdth plates. Eyes directed up- 
wards ; 47 rows of smooth scales ; head elongated, muzzle 
rounded, and much inclined at the sides. S. 250 4- 66. 
Fuliginous brown, with two rows of orbicular spots on the 
back, and a double series of ocellated spots on the flanks. 
An aquatic and viviparous species, which attains a length 
of even 20 feet. Same country as the last. 
3. Boa Cenchria. — Of less size than the two last. A 
terrestrial species, with the habits of the Boa Constrictor. 
Head almost as in the two last, but the labial plates are 
hollowed into a gutter, and the vertical plates are replaced 
by small scales of an irregular form ; tail short ; nostrils 
open and lateral ; 35 rows of smooth scales. S. 240 -f 
48. Of a yellowish red-brown ; above ornamented with 
a double suite of orbicular spots, bright, and bordered with 
black; three rows of spots, less broad, and dark coloured, 
on the sides. The spots are often confluent, forming a 
reticular design. Country the same as the preceding 
species. 
4. Boa Canit^a. — ^Well characterized by its green tints, 
relieved by white lozenge- formed, dorsal spots ; below 
yellowish. Anterior teeth very long ; body strongly com- 
pressed, and particularly adapted for being rolled inwards ; 
