•324 ME. H. M. BEENAED OJSI THE 



fig. 15 a). The distal portions of these limbs, however, which are leg-like, are arranged 

 parallel to the median plane. 



The pedipalps are carried in this leg-like fashion in the Aranese, the Phalangidfe, and the Schizo- 

 notidae ; whereas in the Thelvphonidse, Phrynidae, Scorpions, and Pseudoscorpions they lie in the 

 horizontal plane. This latter is probably a secondary specialization, in adaptation to a life under 

 stones or bark. 



Starting from some primitive leg-like appendage, such as that figured (PI. XXIX. fig. 5), we can 

 deduce the pedipalps of the Arachnids along two different lines of specialization. From the position of 

 these limbs, they would tend to become sensory organs, as well as seizing organs accessory to the 

 chelicerse. In the Phalangidse, they seem to be little specialized in either direction, being provided with 

 a claw. In the Galeodidse and the Arauese their specialization is almost entirely sensory, while in 

 Schizonotus, Thelyphonus, and Phrynus we Lave variously developed forms of seizing claws and pincers. 

 This specialization reaches its extreme in Scorpio and Chelifer, in which the pedipalps have developed 

 enormously powerful pincers. This chelate condition of the pedipalps has thus, I think, departed 

 furthest from the primitive leg-like pedipalp of the ancestral form. 



In Galeodes the pedipalps are very long (PI. XXIX. fig. 3), in Uliax very short 

 (fig. 4) ; in both cases they are powerful limbs, and, without having any definite claws 

 or seizing organs, almost certainly help to hold jjrey by encircling it. The chief function 

 of these limbs is undoubtedly sensory. They are extremely hairy, specially noteworthy 

 being the long silken hairs (a few of which are shown in PL XXIX. fig. 3, and their 

 insertions in the cuticle in PI. XXXII. figs. 13, 14, 15). Most important, however, are 

 the sensory (olfactory) organs at their tips. These organs are found in free knob-like 

 joints in Galeodes (PL XXIX. fig. 3, PL XXXI. fig. 12), but in Mha.v these joints are 

 fixed (PL XXIX. fig. 4) ; in section, and often to the naked eye, the lines of fusion in 

 this latter case are quite visible. The sensory organ itself will be described in detail in 

 another section (on sensory organs). It is enough here to say that close examination of 

 it shows that it is not an organ " pour grimper ou s'accrocher " as suggested by Dufour, 

 and recently again insisted upon, but a sensory, probably olfactory, organ according to 

 the older view.* 



The coxse are provided with hairy processes on their inner faces distally ; these pro- 

 cesses are immovable (PL XXVII. fig. 14, sj)). In JRliax they are long and cylindrical, in 

 Galeodes short and pointed. These are almost certainly sensory (tactile) in their functions. 



Sensory processes or pads are found at this point on nearly all Arachnids. I have found none in 

 which they are so limb-like as in Rhax. In the Pseudoscorpionidae alone do they appear, at least in 

 some genera, to be movably articulated. They have, in these animals, the laminate form which they 

 have in Scorpio, where they appear to be simply prolongations of the inner faces of the coxae. In the 

 Pseudoscorpionidte, they perhaps assist in holding prey in front of the beak (lO; cf. fig. 5). 



Like the coxae of the other limbs of Galeodes (except the chelicerse), those of the 

 pedipalps are rigidly fixed to the body. They are firmly cemented to the sides of the 

 beak (PL XXVIII. fig. 3). 



* Lichtenstein & Herbst (48), p. f>2 :— " Der scharfe Geruch, der seinen Sitz hauptsiichlich in dem hoUen Knopf 

 an der ISpitze der Vorderfiihlor hat, locket sie dahin," et seq. See also the description of the action of the pedipalps 

 quoted by Murray (57). 



