COMPARATIVE MORPHOLOGY OF THE GALEODID^. 357 



far-reaching consequcuces, and^ indeed, we owe to it the special morjjliology of the group, viz. : the 

 character and position of the anterior seizing-limbs, and the division of the body into an anterior loco- 

 motory region and a posterior highly distensible food-bag. 



In adaptation to this liquid food we have apparatus (1) for preventing the escape of the juices crushed 

 out in front of the mouth, and (2) for straining them so that no solid matter finds its way into the 

 alimentary system. 



Special Apparatus for conducting and straining juices. — The juices flowing from 

 the wound made by the chelicerte are conducted towards the tip of the beak by 

 bushy rows of jilumose hairs Avhich run along the digits of the chelicerge on their 

 inner sides. The juices are strained by the sieve-like arrangement at the tip of the beak 

 already described (PI. XXVIII. fig. 6). In one of my series of sections, the outside of 

 this sieve is thickly covered witli moth's feathers and scales. A few of these were also 

 found in the digestive tubules, and in each case embedded in small masses of blood- 

 plasma, which, apparently on account of their presence, had not been taken in and turned 

 into food-globules by the digesting-cells (i i). 



Thelyphonus also has a beak, but it is enclosed between the basal joints of the pedipalps, which are 

 fused below it, but are open above it (PI. XXVIII. fig. 12) . The ehelicerte crush the prey into the channel 

 thus formed by the coxse of the pedipalps, and the juices are drawn in by the powerful pumping- 

 apparatus. They are strained by transverse rows of fine hairs, which line the aperture (figs. 12, 13, st). 

 In Phrynus the pedipalps are not fused below, but their inner faces are covered with fine hairs and 

 they can be apposed. Their upper inner faces are provided with specialized " gutters," i. e. one on each 

 side, for conducting the juices to the mouth, as Gaubert (32) has already pointed out. 



The Phalangidse are also said (McLeod) to have similar gutters, or, as they have been somewhat 

 inappropriately called, " pseudotrachese." In Scorpio, the coxse of the pedipalps, which are generally 

 adapted among the Arachnids to prevent the escape of fluids, have been forced apart by the squeezing 

 forward of the two following coxie, which, again, may have been forced forward by the anterior translocation 

 of the genital aperture. To prevent the escajje of juices, therefore, processes of the coxae of the first and 

 second pairs of legs have developed forward, and together form a sort of spoon-like structure under the 

 mouth (PI. XXVIII. fig. 9, /j) . Fine hairs prevent the juices from escaping between these coxal processes, 

 and a pair of "gutters" [Euscorpw] conduct back any which happen to be escaping in that way 

 (PI. XXVII. fig. 9 6,^). 



The Spiders apparently apply the oral aperture to the wound in the prey, the dense tufts of hairs 

 on the parts bordering the mouth and on the coxai of the pedipalps hindering the escape of the juices. 

 The sti-aining-apparatus is very highly developed. The entrance to the oesophagus between the labrum 

 and labium is a long transverse slit provided with transverse rows of fine straining-hairs ; between these 

 rows of hairs are gutters sloping upward and inward to open, in some cases, through windows into a 

 central gutter which itself gradually widens into the cesophagus proper. The latter is prevented from 

 collapsing under the powerful sucking-action by its solid chitinous dorsal wall. 



The only exception I know to this order of things is the case of an unknown Phalangid (already 

 mentioned), which I cut in sections for some special purpose, and found, to my astonishment, that behind 

 the brain the oesophagus formed a large muscular ' crop ' which was full of solid particles. As there 

 were none in the stercoral pocket, I presume that this is some special arrangement of the sucking-apparatus, 

 and that the solid matter is again ejected through the mouth. 



The Mid-gut. — The oesophagus, in Galeodes, is not in a continuous straight line with 

 the mid-gut, but doubles back slightly on itself, so that, with the mid-gut, it form.s an 

 S-shaped bend (PI. XXXI. fig. 5), the lower loop of which gives rise to the blind pocket 



