ATRACTASPIS INORNATUS. 
drangular, the outer side of each longer than the inner ; fronto-nasal plates 
five-sided, the outer extremity of each two-sided ; frontal plate six-sided, the 
two sides, which form the anterior margin of the plate, nearly in a straight 
line, the two hindermost sides converge and join each other at an acute angle ; 
occipital plates six-sided ; palpebral plates small, narrow, and quadrangular ; 
temporal plates two, large, the anterio-inferior one five-sided, its lower portion 
situated between the fourth and fifth labial plates, the upper and posterior 
plate oblong and quadrangular. Nasal plates small, oblong, and quadran- 
gular ; naso-frenal plate five-sided ; preocular plate small, subovate, or 
slightly five-sided ; post-ocular plate small. The plates of the upper lip, 
exclusive of rostral, five ; the first very small, the three following qua- 
drangular, the third and fourth, measured vertically, of considerable length, 
the one extends to the preocular plate, the other to the eye, the fifth or last 
plate is oblong, five-sided, and placed obliquely at the angle of the mouth. 
The labial plates of the lower jaw, exclusive of the mental plate, three; the 
first and second very small, the third long, narrow, and widest behind. The 
mental plate is triangular and very small ; the submental plates, -which 
consist of one pair, are somewhat four-sided, the hinder side of each oblique, 
the anterior side slightly arched ; anterior to these plates, between them and 
the mental plate, the first narrow labial plate of each side extends inwards 
and joins its fellow of the opposite side. The fangs, the only teeth in the 
upper jaw, are generally two on each side, equally developed, both very long, 
rather slender, and when recumbent reach almost if not quite to the angle of 
the mouth ; the palatal and mandibulary teeth are very small. The poison 
bag is long, narrow, and broadest about midways between its extremities 
[fig. cl — a), its tube is short ; the muscular structures which compress the sac 
to expel the poisonous fluid are abundant, powerful, and effective. The scales 
of the body are scarcely imbricate, they are disposed in oblique transverse 
rows, the number in each row, at the middle of the body, twenty ; the 
four on each side, nearest the abdominal plates, are much broader than 
the dorsal ones, the former are distinctly six-sided, the latter almost rhom- 
boidal, at least the anterior and posterior sides are very short. Caudal 
scales in shape somewhat like the lateral scales of the body, and are dis- 
tinctly six-sided. Abdominal and subcaudal plates narrow and convex, and 
in one specimen were 255 = 20 and in another 225 = 21 . 
