SYNOPSES OF NORTH-AMERICAN 
INVERTEBRATES. 
XVI. THE PHALANGIDA. 
NATHAN BANKS. 
THE Phalangida, or the Opiliones as they have been called 
by some authors, form a very distinct order of the Arachnida. 
The cephalothorax is of one piece, but often presenting one or 
two incomplete transverse furrows. There is also a furrow 
on each side, which is supposed to indicate that the portion 
beyond is a part of the pleura. On this part on each anterior 
side there is a small, somewhat circular depression, with a 
membranous bottom; these are called the lateral pores. On 
the middle line of the cephalothorax, and frequently near the 
anterior margin, is a rounded elevation, with a simple eye on 
each lateral face ; this is the eye-tubercle, or eminence. The 
abdomen is united to the cephalothorax by the whole of its 
breadth, so that there is no trace of a pedicel. It is always 
quite broad when compared to its length, never slender, and 
usually quite high; in the males it is often tapering behind. 
There are considered to be eight segments in the abdomen, 
but in many forms the basal and median ones are poorly 
defined on the dorsum ; on the venter there are usually six 
distinct segments. The underside of the cephalothorax is 
occupied by the coxze and a median piece similar to and often 
called a sternum. It is, however, something quite different ; 
It is the basal ventral segments advanced forward over the 
bases of the coxze ; it carries with it the opening of the genital 
organs, which thus, in certain forms, appears to issue close to 
the mouth. This advancement of the abdomen is so pro- 
nounced in many of our common forms that the coxa are 
crowded at base and so appear to radiate from a central point. 
The legs are usually very long and slender, though tarsi and 
