834 CLASS V. ARACHNIDA. 



eggs are maturing. There is no post-anal tail or spine of 

 any kind. 



The chelicerae are small and chelate, the movable joint of the 

 chelae being pierced by the orifice of the duct of the spinning 

 glands (see below). The chelicerae in certain families also bear 

 a small toothed organ called the " galea," and in all the members 

 of the group they bear a comb-like ridge, the " serrula," and a 

 process, like the antenna of a Lamellicorn, termed the " flagellum." 

 All these structures probably have something to do with the 

 silk-spinning. The large pedipalps recall those of the scorpions 

 and probably explain the second name of the group. They 

 have six joints and are chelate, and their bases are produced in 

 towards the mouth. The legs are slender and consist of from 

 five to eight joints terminating in two claws, between which is 

 a sucker like a pulvillus. 



The generative pore lies on the first abdominal sternum which 

 is also pierced by the ducts of certain abdominal glands. The 

 stigmata lie, a pair behind the first, and a pair behind the second 

 abdominal sternum, rather to the side. 



The alimentary canal consists of a sucking-pharynx followed 

 by a short oesophagus which traverses the chief nerve ganglion ; 

 the stomach gives off an unpaired diverticulum which passes 

 ventrally and two lateral lobed diverticula which occupy a 

 large part of the body ; it then passes into a coiled or looped 

 intestine, a very unusual feature in an Arachnid. The stercoral 

 pocket is small and no malpighian tubules are known. 



The tracheae of the first pair of stigmata pass forward and 

 those of the second pair backwards. Rudimentary stigmata 

 are described on the third and remaining segments of the 

 abdomen. 



A pair of coxal glands are well developed ; they are U-shaped 

 and internally the closed end consists of a syncytium of cells. 

 They open on the coxae of the third pair of ambulatory 

 limbs. 



A pair of spinning glands lie in the cephalothorax and open 

 to the exterior on the movable joint of the chelicerae. There 

 are also large glands in the abdomen which open by two median 

 papillae, one under the genital operculum and one on the anterior 

 edge of the third abdominal segment ; they probably produce 

 a secretion which keeps the eggs together. 



