Palaeozoic Arachnid a of North America. 



109 



ventral segment, or behind the fourth coxae. In the family Phalan- 

 gioidae the position of the spiracles is varying, in some species there is 

 a spiracle on each tibia. Genital organs opening with a peni^ or 

 ovipositor on the first abdominal sternite. Oviparous. 



Fig. 66. 



Figure 66. — Stylocellus beccaniThoreW, from Sumatra ; male viewed from above. 

 (From Hansen and Sorensen, On two Orders of Arachnida, 1904.) 



This order shows close relation to Haptopoda and Phalangiotarbi. 

 To facilitate the understanding of the species belonging to the last 

 named order, I reproduce here two figures showing the skeletal struc- 

 tures of an Opilionid belonging to the family Sironoidae of the sub- 

 order Cyphophthalmi. 



To this order belong probably the following Carboniferous arachnids 

 from Europe : 



