58 HETERODON SIMUS. 
over the eye; the rest of the orbit is completed by ten or eleven small quadri- 
lateral plates, the inferior of which rests on the superior labial. ‘The occipital 
plates are pentagonal, and very large; the frontal are pentagonal and broad; the 
anterior frontal plates are rounded and smaller; between these frontal plates, and 
on the mesial line, is a long, slender, intermediate or azygous plate, extending 
from the vertical to the rostral, and surrounded on each side with six or eight 
scales or small plates that separate it completely from the frontal. The rostral 
plate is very large, and represents a three sided pyramid, with its broadest surface 
directed forwards, and with its summit turned upward, and rounded, unlike the 
pointed snout in the Heterodon platirhinos, which gives to this animal a peculiar 
aspect, and much more like the snout of a hog. ‘There are three nasal plates, the 
posterior one large and triangular, with its basis lunated for the nostril, and 
connected behind by a large loral plate with the orbit of the eye; the anterior 
nasal are quadrilateral and smaller, and in some individuals are consolidated into 
one plate; the superior labial plates are eight in number on each side, quadri- 
lateral, and very small anteriorly, but much larger posteriorly, and of these the 
sixth and seventh are largest. 
The nostrils are lateral and near the snout. The eyes are rather large, the 
pupil black, with the iris light grey. The neck is not contracted, and is covered 
above with small sub-hexagonal scales. The body is elongated, but tolerably 
robust, though flattened, and covered above with similar scales, carinated. ‘The 
tail is short and thick. 
Cotour. The head is dusky-brown above the snout, with a black band extending 
transversely between the anterior part of the orbits. The vertical plate, as well 
as the centre of the superior orbital plate, is lightest brown, so as to present the 
appearance of a white band across the vertex; the occipital plates are black, and 
from them descends laterally on each side of the neck an elongated black blotch, 
increasing in descent, and having a white blotch between them in the mesial line 
—these two lateral marks represent the expanded wings of an insect, while the 
centre black spot on the occipital plates form the body. ‘The upper jaw and 
