76 Dr. Russell and Mr. Home’s Observations, See. 
Explanation of the Figures. See Plate III. 
Fig. 1. Represents a side view of the head of the Fer-de- 
lance or yellow snake of Martinico, to show the external ap- 
pearance of the orifice, with its relative situation to the nostril 
and the eye. The parts are delineated of their natural size. 
Fig. 2. A side view of the head of the same snake, in which 
the bag is laid open. At the aperture of the cavity, which opens 
towards the cornea, there is a double row of small projecting 
points. 
Fig. 3. The cuticle of the rattle-snake, after it had been cast 
off' from one side of the head, represented of its natural dimen- 
sions. In this view, the internal surface only of the cuticle is 
seen. There is an aperture, of an irregularly oval form, which 
is the opening of the nostril : a little farther on is the lining of 
the rounded bag, in a distended state; nearer the eye is the 
cavity communicating with the space before the cornea, it is of 
an oval form, and has a narrow neck ; beyond this neck is the 
transparent cornea, which in the snake is cuticular, and is shed 
with the external covering of the other parts. Through the 
transparent cornea, a bristle is seen passing before its external 
surface into the cavity. 
This figure is taken from a preparation in the Hunterian 
Museum. 
