1889.] REV. 0. P. CAMBRIDGE ON NEW ARANEIDEA. 45 
Family THERIDIIDE. 
Gen. nov. CHASMOCEPHALON. 
Cephalothorax short-oval ; caput large and very convex above ; 
the ordinary oblique indentations dividing it from the thorax are 
greatly exaggerated, forming a deep chasm or cleft on each side. 
The posterior extremity of the thorax is broad and strongly indented 
or excavated in a curved form, forming a kind of socket into which 
the pedicle joining it to the abdomen fits. 
Eyes of very unequal size; in three well separated groups occupying 
the whole width of the fore part of the caput; the anterior pair 
of the central group smallest, the rest nearly equal. The clypeus 
considerably exceeds in height half that of the facial space, occupying 
about, or even more than, two thirds of it. 
Legs slender, moderately long, 1, 4, 2, 3 ; furnished with hairs and 
bristles only. 
The maville are short, curved, inclined towards the labium, and 
somewhat pointed at their extremities on the inner side. 
Labium short, broad, and round at the apex, which reaches nearly 
to the extremities of the maxille. 
Abdomen considerably elevated in front and projecting greatly 
over the base of the thorax, with which it is connected by a distinct 
pedicle, the abdomen having also a kind of socket or excavation to 
receive it. Besides the usual spiracular openings there is a long 
transverse one beneath the abdomen just in front of the spinners. 
CHASMOCEPHALON NEGLECTUM, sp. n. (Plate II. fig. 6.) 
Adult male. Length scarcely over half a line. 
The surface of the cephalothora«, which is of aclear bright brownish- 
red hue, is granulose; the oblique cephalic indentations are deep 
and sharply cut, looking as if they would sever the caput from the 
thorax; the other normal (thoracic) grooves are also of somewhat 
the same nature, though very much less strong; the posterior end 
of the thorax is broad and deeply excavated; the hinder part of 
the caput is well rounded, the fore part flatter. 
The eyes of the central group form a trapezoid whose anterior side 
is much the shortest; the pair of eyes composing this side are very 
minute and contiguous to each other. The posterior pair are oval, 
large, contiguous, and of a pearly hue, their diameter equalling more 
than double that of the anterior pair; each of these is separated 
from the anterior eye opposite to it by an interval only about equal 
to the diameter of the latter. The hind lateral eye on each side is 
separated from the hind central next to it by about 13 diameters of 
the former, and each fore lateral eye, which appears to be rather the 
largest of the eight, is contiguous to its hind lateral eye. The lateral 
eyes are also pearly, the fore centrals being a little darker. 
The Jegs are dull orange-yellow; the hairs longish, but not very 
numerous, and there are also a few prominent bristles. 
The palpi are unfortunately missing. 
Falces moderately strong, rather long, straight, and a little inclined 
