PHALANGIDEA. 839 



The legs of the Phalangidea form one of 

 their characteristic features ; they are as 

 in the Araneida seven- jointed, but the 

 joints except the area which is fused with 

 the cephalothorax are often much elon- 

 gated and the legs are very long and FlG 552 ._ chelicerae and 

 brittle. The tarsi are multiarticulate ;! TWt 

 and terminate in one or two claws. The front - 

 first and in many cases the second legs bear gnathobases. 



There is a thin- walled pharynx with teeth within the mouth, 

 and just behind it ; traversing the nerve-mass is a moderately 

 fine oesophagus which dilates posteriorly and then enlarges 

 into a spacious stomach -f- intestine which passes straight to the 

 anus. This stomach -|- intestine bears (some thirty) caeca of 

 varying sizes, usually paired ; these however remain distinct 

 and do not become entangled together to form a gland like the 

 so-called liver of the Araneida. The anus is terminal. Phalan- 

 gids, unlike spiders, eat solid food which may be triturated 

 by the gnathobases and by the pharyngeal teeth. 



The heart is a dorsal tube with three chambers and three 

 pair of ostia ; little more is as yet known about the circulatory 

 system. The tracheae provide a complex system strengthened 

 by spiral thickenings ; the stigmata lead at first into large spacious 

 chambers from which the fine tracheae are given off. 



A pair of malpighian tubules open into the intestine, and a 

 pair of coiled coxal glands, bearing internally a well-marked 

 vesicle, open on the base of the third ambulatory leg. There 

 are no spinning glands except in the Cyphophthalmi. 



The supra-oesophageal ganglion gives off nerves to the eyes 

 and to the chelicerae. It is a somewhat pyramidal-shaped nerve- 

 mass and it passes laterally into the star-shaped composite 

 ventral ganglion which gives off nerves to the other appendages. 

 Posteriorly it gives off a median and two lateral nerves which 

 branch and bear ganglia and supply the structures in the abdomen. 

 There is a stomatogastric system of nerves. 



Both sexes have long protrusible organs for emitting the 

 products of the gonads (Fig. 552 bis}. The ovipositor and the 

 penis are usually retracted ; when extended they are almost as 

 long as the body. Both ovary and testis are annular and the 

 former is papillated with the maturing ova. There is a spacious 



