224 DIVING SPIDERS. PEDIPALPI. 



when it has arrived there, it gets beneath its lower edge, and 

 allows the bubbles of air which it had entangled to ascend into 

 it. Then returning to the surface of the water, it brings down 

 a fresh supply of air ; and in this manner it gradually fills the 

 bell, which then presents a beautiful silvery or glistening appear- 

 ance, when seen beneath the surface of the water. This process 

 is strikingly analogous to that, which was first employed to 

 renew the air in Diving Bells ; barrels of air being sent down by 

 means of weights, and their air being allowed to pass into the 

 bell, by means of a flexible pipe, when they had been sunk to a 

 lower level. 



760. Section II. PEDIPALPI. This section is distinguished 

 by the large size of the palpi, which resemble extended arms, 

 and which are furnished at their extremities, either with moveable 

 hooked claws, or with a pair of pincers, composed of two fingers, 

 one fixed and the other moveable, like those of Crabs and 

 Lobsters. The abdomen is composed of very distinct segments ; 

 and is destitute of spinnerets at the tip. The entire body is 

 encased in a hard skin. The cephalothorax is composed of a 

 single piece, and is furnished with six or eight ocelli or eyelets. 

 The number of pulmonary sacs is four in one of the two families 

 of which the section is composed, and eight in the other. In the 

 first of these families, THELYPHONIDJE, the general form is that 

 of the Spiders ; so that the species included in it are commonly 

 ranked as such. They are, however, at 

 once distinguished by the large size of the 

 palpi, and by the absence of spinnerets. 

 They differ from the Scorpions, on the 

 other hand, in the form of the abdomen ; 

 and in the absence of a sting at its extre- 

 mity. The tarsi of the two fore-legs differ 

 from the others in a remarkable degree ; 

 being composed of numerous joints, so 



FIG 446. PHRYNUS RENI- , , 



FORMIS, reduced. slender and prolonged as to resemble 



threads, and being destitute of the usual 



hook at its extremity. These Arachnida inhabit only the 



hottest parts of Asia and America ; very little is known of 



their habits. 



