SYNOPSES OF NORTH AMERICAN 
INVERTEBRATES. 
XX. FAMILIES AND GENERA OF ÄRANEIDA. 
NATHAN BANKS. 
Tue body of a spider is very distinctly divided into two parts : 
the anterior, or cephalothorax, or carapace, and the posterior, or 
abdomen. The cephalothorax is supposed to be the equivalent 
of the head and thorax of in- 
sects, Near the middle of 
the cephalothorax is a dorsal 
or median groove; from this 
groove radiate furrows, called 
radial furrows. The region 
of the cephalothorax between 
the anterior pair of furrows 
is called the pars cephalica, 
or head; the part behind is 
known as pars thoracica. 
The eyes are situated upon 
the front part of the pars 
cephalica; the region they 
occupy is known as the eye- 
region, eye-area, Or ocular 
area. The eyes are usually 
eight in number, sometimes 
six, more rarely two or none. 
They are arranged in trans- 
verse rows, often two, some- 

mandible; 4, eyes; <, pars cepha- 
times three or four. Refer- cell e, dorsal groove; g, ab- 
ences to the eyes are in the Jemen; + spinnerei; e apti 
form of abbreviations, S. E., 
meaning side eyes; A. E. anterior eyes; P. E., posterior eyes ; 
M. E., middle eyes; P. M. E, posterior middle eyes; A. 5. Es 
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