THE PYTHONS AND BOAS 2555 



ously. To European palates, snakes would probably be highly unacceptable as 

 food, however temptingly they might be dressed; but in Eastern South America, 

 the flesh of the boa is regarded as a most dainty dish, while its fat is reputed to be 

 highly efficacious in the healing of various diseases. The skin is used to ornament 

 saddles and bridles, and for other decorative purposes. None of the other members 

 of the genus attain dimensions equal to those of the common boa, the Malagasy spe- 

 cies being the smallest of all. 



The last representative of the section of the subfamily in which the 

 head is well defined from the neck, and the tail more or less prehen- 

 .sile, is the keel-scaled boa (Casarea dussumieri} of Round island, 

 near Mauritius, distinguished as a genus by the keeling of the scales, and the long 

 tail; its other general characteristics being similar to those of the true boas, except 

 that the nasal shields of the head are separated by a pair of internasals. This 

 snake, which attains a length of about four feet, and has a prominent and obliquely 

 truncated muzzle, is either uniform pale brown above, or brown with two dark 

 stripes and a lateral series of small spots down the body, a dark streak on each side 

 of the head through the eye, and the under parts either plain yellow or yellow 

 spotted with black, the under side of the tail always having such spots. 



The snakes of this genus, together with those of three allied genera, 

 which are the remaining members of the family, may be distinguished 

 at a glance from the boas and their allies by the gradual passage of the head into 

 the body without any constriction at the neck; while they are further characterized 

 by the tail being, at most, only . slightly prehensile. From their allies, the sand 

 snakes are distinguished by the small scales being either smooth or singly keeled, 

 and by the head being covered with small shields, of which the rostral is enlarged. 

 The eye is small, and sometimes minute, with a vertical pupil; while the body is 

 cylindrical, and the very short tail, which is frequently without any power of pre- 

 hension, has a single row of shields on its lower surface. These snakes are repre- 

 sented by seven species, with a geographical distribution including Northern and 

 Eastern Africa, and Southern and Central Asia, as well as a part of the extreme 

 southwest of Europe. The best-known species is the Egyptian sand snake (Eryx 

 jaculus) , which has a length of about two feet, and is an inhabitant of the Ionian 

 islands, Greece, Southwestern and Central Asia, and the north of Africa. In color 

 it is very variable, the upper parts being in some examples pale grayish, reddish, or 

 yellowish brown, ornamented either with dark brown or blackish transverse blotches 

 or alternating spots, while in other cases the general color is brown with pale spots. 

 A dark streak runs from each eye to the angle of the mouth; the under parts are 

 either uniform white, or white with blackish dots, and there is a more or less dis- 

 tinct dark streak along each side of the tail. This species is exceeded in size by the 

 Indian sand snake (E. johni}, which attains a length of over a yard, and inhabits 

 the plains of Northwestern, Central, and Southern India. This snake is generally 

 banded, but the young may be of a uniform pale coral-red color. Although re- 

 sembling the boas in being nocturnal, these snakes are quite different in their mode 

 of life, inhabiting open sandy plains, and feeding on small mammals, lizards, and 

 worms. In search of their Drey they frequently enter holes and crevices among 



