190 
ZOOLOQT. 
to enter the mouth of their parent, wlio swallows them and 
keeps them in her stomach until the danger is past. 
Most snakes resemble in color the ground or soil they fre- 
quent; some being, as in the rattlesnake of the western 
plains, of the color of the soil in which they burrow; the 
little green snake is of the color of the grass through which 
it glides; others are dull gray or dusky, harmonizing with 
the color of the trunks of trees on which they rest. The 
poisonous coral-snake {Elaps) of the Central American for- 
ests is, however, gayly and conspicuously colored; indeed, it 
Ftg. 233. — Head of the l attlesnake. o, a. poison grland and its excretory duct; c, 
anterior temporal muscle; /, posterior temporal muscle; r/. di^astricus; h. ex- 
ternal pterygoid muscle; ^^ middle temporal muscle; q, articulo-maxillary 
ligament which joins the aponeurotic capsule of the poison gland; r, the cer- 
vical angular muscle; vertebro-mandibular muscle; costo -mandibular 
muscle. After Duvernoy. 
can afford to be brightly colored, as no birds dare to at- 
tack it. 
The Salenoglyph poisonous snakes may always be recog^ 
nized by their broad, flattened heads, and usually short, 
thick bodies. The poison gland of the rattlesnake (Fig. 
233, a) is a modified salivary gland. The two fangs are 
modifications of maxillary teeth, each of which has been, 
so to speak, pressed flat, with the edges bent towards each 
other, and soldered together, so as to form a hollow cylin- 
der open at both ends, the poison duct leading into the 
basal opening. When the fangs strike into the flesh, the 
