230 ELEMENTS OF COMPARATIVE ZOOLOGY. 



joints being much larger than the terminal five. The ab- 

 domen ends in a very efficient poison-sting. On the lower 

 surface of the basal abdominal segments are the openings 

 to four pairs of lungs. Scorpions are not found in cold 



v- 



FIG. 105. Under surface of scorpion (Buthus) showing the combs and 

 outlines of the lung-sacs. 



climates, but in the warmer regions they abound, and their 

 stings, which rarely prove fatal to man, renders them un- 

 pleasant companions. 



ORDER II. ARAKEIDA. 



The Araneida, or spiders, have the cephalothorax and ab- 

 domen unsegmented, but sharply separated from each other 

 by a narrow waist. In front are the poison-jaws (man- 

 dibles), each with a poison-gland inside. At the tip of the 

 lower surface of the abdomen are two or three pairs of 

 spinnerets. These are modified appendages with numbers 

 of small openings at the tip. Connected with each spinneret 

 is a gland which secretes a fluid with the property of hard- 

 ening as soon as it comes in contact with the air. This is 



