XU COXAL AND POISON GLANDS 337 
The COXAL GLANDS are two elongated brownish-yellow bodies, 
situated beneath the lateral diverticula of the stomach, and 
between it and the endosternite. They present four slight pro- 
tuberances which project a short distance into the coxae of the 
legs. The glands appear to be ductless, but their function is 
thought to be excretory. They were first observed in the 
Theraphosae. 
All Spiders possess a pair of POISON-GLANDS, connected by a 
narrow duct with a small opening near the extremity of the fang 
of the chelicerae. The glands are sac-like bodies, usually situated 
in the cephalothorax, but sometimes partially (Clubiona) or even 
entirely (Mygale) in the patura, or basal joints of the chelicerae. 
Each sac has a thin outer layer of spirally-arranged muscular 
and connective tissue fibres, and a deep inner epithelial layer of 
glandular cells. The cavity of the gland acts as a reservoir for 
the fluid it secretes. The virulence of the poison secreted by 
these glands has been the subject of much discussion, and the 
most diverse opinions have been held with regard to it. The 
matter is again referred to on p. 360. 
VOL. IV Z 
