368 ARACHNIDA. 



the young are born alive, it cannot be looked upon as an ovipositor, or 

 as furnishing any secreted defence for the ova. 



(950.) In conclusion, it seems evident, from the above-recorded cir- 

 cumstances connected with the organization of the Acaridan Arach- 

 nidans, that much of their history is as yet involved in great obscurity ; 

 sufficient, however, has been said to show that much interest is attached 

 to many points in the economy of these minute creatures. 



(951.) The rest of the Arachnidans breathe by means of lungs, or, 

 as they are more properly designated, pulmonary branchice, and conse- 

 quently, in contradistinction to the last-mentioned, are called by zoo- 

 logists ARACHNIDA PULMONARIA ; such are the Scorpions and /Spiders. 



Fig. 184. 



Scorpion (ventral aspect). 



(952.) The PEDIPALPI, forming the second division, are at once 

 recognized by the peculiarity of their external configuration. Their 

 palpi (the representatives apparently of the maxillary palpi of Insects) 

 are exceedingly strong, and furnished at their extremity with a pre- 

 hensile forceps ; the hinder part of the body, corresponding with the 

 abdomen of Insects, is much prolonged, and composed of numerous 

 articulated segments, terminated in the Scorpion tribe by a sharp unci- 

 form sting (fig. 184) armed with a venomous secretion. 



(953.) The third section embraces the ARANEID^E, or Spiders, di- 

 stinguished by having the abdomen short and globular, and furnished, 

 moreover, near its posterior termination with spinnerets, by means of 

 which these animals manufacture silken filaments applicable to a great 

 number of purposes, and especially employed in constructing what is 

 usually named the spider's web. The maxillary palpi in the females 

 are simple, and more or less resemble feet ; but in the males they often 

 form a remarkable apparatus, to be described in another place. The 



