THE ARANEINA. 



327 



While the last-mentioned forms lead from the Arthrogastra 

 to the Acarina, the pulmonate Phrynidce, or Scorpion-spiders 

 (Thelyphonus, Phrynus), are in many respects intermediate 

 between the Arthrogastra and the Araneina. 



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Fig. 88. — Mygale aementaria.—A, female of the natural size : At, chelicerae ; rv', 

 pedipalpi ; v', vi', maxillary feet; vn', vni', thoracic feet ; Cth, cephalo-thorax. 

 B, the last joint of the pedipalpus of the male much magnified. C, terminal joint 

 of the chelicera At, with the poison-gland. D, the left pulmonary sac viewed from 

 its dorsal aspect: Stg, stigma; Pm, pulmonary lamellae. E, the two arachnidial 

 mammillae of the left side— the smaller Sp 1 is situated on the base of the large one, 

 Sp 2. (After Dugds, " Regne Animal.") 



The Araneina. — The Spiders stand in somewhat the same 

 relation to the Scorpions as the brachyurous to the macrurous 

 Crustacea. That part of the body which lies behind the 

 cephalo-thorax and answers to the free somites of the body 

 of Scorpio is swollen, and presents no distinct division into 

 somites. 



The cheliceras are subchelate, that is to say, the distal 

 joint is folded down upon the next, like the blade of a pocket- 

 knife upon the handle. The duct of a poison-gland, lodged in 

 the cephalo-thorax, opens at the summit of the terminal joint. 

 The pedipalpi are filiform, and, in the males, their extremities 

 are converted into singular spring boxes, in which the sper- 

 matophores are received from the genital apertures and con- 

 veyed to the females (Fig. 88, B). 



The pulmonary sacs, two or four in number, are similar to 

 those organs in Scorpio, and are placed in the anterior part 

 of the abdomen ; a tracheal system is also present, a pair of 

 sternal stigmata, situated either behind the pulmonary sacs, 

 or at the end of the abdomen, leading* into two more or less 

 branched tubes. There is a complex pharyngeal apparatus, 



