444 ARACHNIDA PHALANGIDEA CHAP. 



Ischyropsalis) the chelicerae are remarkably long, and may 

 considerably exceed the total length of the trunk. 



The pedipalpi are six-jointed, possessing coxa, trochanter, 

 femur, patella, tibia, and tarsus. They are leg-like and are never 

 chelate, but in some forms terminate in a single movable claw. 

 The coxal joints are provided with maxillary plates. 



The legs are normally seven-jointed, as in Spiders, the 

 penultimate joint being the metatarsus. The tarsus is always 

 multi-articulate, the number of its joints being variable. It 

 bears terminally one or two simple claws. " False articulations " 

 (where the parts are not inserted one into the other, but are 

 only marked off by a membranous ring) are of frequent occur- 

 rence in the legs of these creatures. The first legs, like the 

 pedipalps, bear maxillary plates, as do also the second in most 

 Phalangids. The maxillae of the second legs are, however, 

 entirely absent in Nemastoma, and rudimentary in the Gony- 

 leptidae and the Ischyropsalidae. The coxae of the legs are all 

 largely developed, but are not capable of free motion, being 

 soldered to, and practically forming part of, the cephalothoracic 

 floor. In some forms they are only separated from one another 

 by slight grooves. The extreme length of the legs, and their 

 hard and brittle nature, are characteristic features of the 

 Phalangids, though in some species (Trogulidae) they are com- 

 paratively short. The first pair of legs are always the shortest, 

 and the second the longest. 



The sexual organs of Phalangids are ordinarily concealed, and 

 the sexes can only be distinguished by certain very variable 

 secondary characters, the males being usually smaller of body 

 and longer of leg than the females, besides being more 

 distinctly coloured and being armed with more numerous 

 and longer spines. Sometimes the male chelicerae are highly 

 characteristic. 



Phalangids are usually destitute of spinning organs, but such 

 have been discovered, in a rudimentary state, in the Cyphoph- 

 thalmi, which are said to spin slight webs. 



Internal Structure. — In Phalangium the mouth leads up- 

 wards into a membranous pharynx, wider than that of Spiders, 

 but narrowing into an oesophagus which passes between the 

 cerebral and thoracic ganglionic nerve-masses. It then turns 

 backwards over the thoracic ganglion, being slightly dilated at 



