CHAPTER XXV: THE BLIND SNAKES; FAMILY 



GLAUCONIID^, AND THE DWARF BOAS; 



FAMILY BOID/E 



A Few Northern Representatives of Tropical Families 



Both of the families embraced in this chapter are essentially 

 tropical. Of the Blind Snakes — Glaucaiiiidce, two typical repre- 

 sentatives extend northward from Mexico into the extreme 

 southern United States. Of the Boidce — the family of great 

 constrictors (Boas and Pythons) — four small, rather degenerate 

 species are found in North America. In form and habits these 

 families are widely diflFerent, but both show vestiges of a pelvis 

 and hind limbs. With the Glauconiidce — though the rudiments 

 of the pelvic girdle and the hind limbs are most pronounced 

 of any living snakes — the hind limbs are quite concealed. On 

 most of the species of Boidce, the rudimentary hind limbs are 

 visible externally, as claw-like spurs; these protuberances 

 are movable and represent the tip of the limb. 



The Blind Snakes — Family Glauconiidce: This family of 

 degenerate, worm-like snakes, is composed of two genera ;/4«om- 

 alepis — I Mexican species, and Glaiicotiia — about 30 species, 

 which inhabit semi-tropical America, Africa and southwestern 

 Asia. The species are small; the head is usually very blunt 

 and of the same width as the neck; the snout protruding some 

 distance over the mouth. Abruptly tapering — in fact, conical — 

 the tail forms barely more than one-twentieth the total length. 

 There are no broad, abdominal plates, the body being encircled 

 with smooth, glassy, imbricate (overlapping) scales. On the 

 head the scalation is altogether diflFerent from that of most North 

 American snakes (the Coluhridce) ; there are a few large plates, 

 all crowded forward toward the snout. The eyes are buried 

 under translucent shields and appear as mere black dots; they 

 are practically useless except to distinguish between light and 

 darkness. 



These snakes are strictly subterraneous; they burrow long 



2og 



