408 ZOOLOGY 
A pair of poison glands are found in the thorax, closely 
applied to the walls of the stomach. The ducts are coiled, and 
open near the bases of the chelicerae ; muscle fibres are described 
near the orifice, and the contraction of these is believed to eject 
the poison into the wounds caused by the chelicerae. 
Two simple eyes occur in the head. The animals are 
nocturnal, and spend the day under stones or rubbish, or in 
holes in the ground. They are extremely voracious, and live 
on large insects, such as beetles and grasshoppers; they will 
even attack scorpions, and small vertebrates such as lizards 
and mice. The female lays about fifty eggs at a time, and the 
young are hatched in an immature condition. 
Ciass V. Araneida (Spiders). 
CHARACTERISTICS.—Abdomen unsegmented, soft, and stalked ; 
chelicerae with poison glands, pedipalpi leg-like, two or four 
lung sacs, and four or six spinnerets. 
Epeiva diademata is one of the largest species of British 
spider, and at the same time is a very common one, being 
found in its wheel-shaped web in most gardens and woods ; it 
therefore serves as a convenient type of the order. 
The head is united with the thorax, but the abdomen is 
constricted at its base, and being swollen and unsegmented, 
gives a very characteristic appearance to the members of this 
group. 
Appendages of Hpeira. 
1. Chelicerae. 4, 2nd pair of walking-legs. 
2. Pedipalpi. 5. ord 50 Rs 
3. 1st pair of walking-legs. 6. 4th A n¢ 
The chelicerae are two-jointed, the terminal joint being 
curved and pointed, and capable of folding down in a sub- 
chelate fashion; at the base of these appendages lie a pair of 
poison glands, and these pour their secretion through a duct 
which opens to the exterior near the tip of the terminal joint. 
This poison is capable of killing insects and seriously affecting 
larger animals. 
The pedipalpi have a cutting blade-like basal joint which 
takes part in mastication, as is the case in Limulus, Scorpio, 
