322 ME. H. M. BERNAED ON THE 



on the inner faces of these limbs, where, indeed, those of the pedipalps still are 

 {PI. XXVIII. fig. 15). On the other hand, any homology between the buttresses on 

 the outside of the chelicerae of Galeodes with those of the pedipalps would mean that the 

 chelicersB had rotated through nearly 180°, which seems highly improbable. It is safer, 

 then, to conclude that these cheliceral buttresses in Galeodes are new formations, 

 articulating, not the 2nd joint with the coxa, but the coxa with the body, the 2ad joint 

 and the coxa fusing together. It is possible also that the secondary infoldings necessary 

 to form these buttresses gave rise to the areas («) at the sides of the " head." 



I would like in this connection to suggest that the stridulating apparatus formed by 

 a series of folds running along the smooth areas on the inner surfaces of the chelicersB of 

 Solpuga and other genera (PI. XXIX. fig. 1 c.', sir.) may have started from the two hard 

 €dges of a buttress infolding, which, as I have shown, ought at one time to have been 

 present in this place *. That the Galeodidse stridulated by rubbing the chelicerae 

 one against another was described by Pallas t a hundred years ago. Hansen (33) has 

 recently studied the series of stridulating ridges, which are quite coarse enough to have 

 arisen in the way suggested. 



The chelicerae ai'e enormously developed as the only seizing-limbs, the pedipalps having 

 no accessory seizing-apparatus. Observers relate that, in order to bring the beak up 

 to the wound in its prey, the animal works the chelicerse with a sawing motion, holding 

 tight with one to drive the other deeper in f. 



In no other Arachnid are these limbs so powerful as in the Galeodiclse, although in the Spiders and 

 Phalangids and many Acarids they are, as in Galeodes, the only seizing-organs. In other Arachnids 

 — Scorpions, Phrynidse, Thelyphonidse, and Pseudoscorpions — the chelicerse have become secondarily 

 subordinated to the pedipalps as the principal organs of prehension. 



Another difference of great interest is the position of the movable digit of the chelicerse. The 

 Aviculariidse and the Spiders generally, the Phrynidas, Schizonotus and Thelyphonus have the digit 

 folding downward ; on the other hand, the Scorpions, Pseudoscorpions, and Phalangids have the cheli- 

 cerse in the form of pincers, which open from side to side; lastly, in Galeodes and some Aearidse the 

 pincers open and shut dorso-ventrally. Now, starting from the claw-like limb (PI. XXIX. fig. 1 a) as 

 the most primitive, a rotation through 90° would bring the movable digit into the position of that of 

 Scorpio ; but it would require to twist through 180° in order to bring the movable digit into the position 

 found in Galeodes. This, it seems to me, puts rotation as the solution of the difficulty out of court. 



We can, however, account for the different forms of the chelicerse without any excessive rotation. If 

 we start from a primitive limb of three joints (as shown in the diagram PI. XXIX. fig. 1 a), one form 

 would be produced by the two distal joints fusing to form a long claw-like joint which bent down upon 

 the proximal joint (fig. 1 b, c). The second form would be produced by the two distal joints forming 

 pincers which articulate with the body by means of the proximal joint (fig. 1, b' , c'). Some evidence in 

 favour of this view we find in the following facts : — (1) the 3-jointed limbs are only retained in cases where 

 they form pincers; (2) there are no visible traces of any fusion of joints to form the proximal joint of 



* I think traces of this fold may also be seen in markings on the inner faces of the proximal joints of the chelicerae 

 in Scorpio. 



t Lichtenstein & Herbst (48), p. 5S : — " Wenn man sie eingesperrt hat und also reizt, so kann man au der Wuth 

 iind Unerschrockenbeit womit sie auf A lies losgeht Wunder sehen. Sie erregt alsdann durch das Aneinanderreiben 

 ihrer Fangscbeeren eine Art von Gezwitscher und ist in lauter heftigen Bewegung." 



+ The same, p. 28 : — " Kurz, die Solpuge hat das fiirchterUcbste Gebiss unter alien Geschcipfen, nach Verhaltniss 

 ■schrecklicher als der Tiger, das Krokodill, die Brillenscblange und der Haytisch." 



