526 NATURAL SCIENCE. s^pt.. 



Gaubert rejects this view, on the ground that there is no satisfactory 

 evidence that Arachnids can hear at all. He covered the regions 

 where the organs occur in several spiders with a light coat of varnish, 

 and put these, together with uninjured specimens, into one end of a 

 bottle, which he heated ; the spiders which had been varnished did 

 not try to escape from the heat as soon as the others. From this 

 experiment, he concludes that the function of the lyriform organs is 

 that of appreciating differences in temperature, " et peut-etre aussi 

 d'autres sensations generales." This result can hardly be regarded 

 as conclusive ; the closing of the slits by a coat of varnish would, of 

 course, diminish the creature's power of feeling heat, but this does 

 not prove that the organs have not another and more specific use. 

 The thin bands certainly suggest the reception of vibrations as their 

 function. The experiments of the Rev. O. P. Cambridge (" Spiders 

 of Dorset," p. 582) on Epeira diademata seem conclusively to prove 

 that that species, at least, can hear. Moreover, the presence of 

 stridulating organs in certain male spiders points decisively to a 

 power of hearing in their females. 



Much attention has been paid by Gaubert to the pecten of 

 scorpions ; he describes in detail these organs in Bnthus. They are 

 worked by a complicated system of muscles, turning the whole 

 appendage, and also moving the teeth. The cuticle of the teeth is 

 raised into numerous papillae, each having a pore filled by a nerve- 

 ending. The function of the pecten seems to be undoubtedly tactile, 

 with special reference to copulation. The sense-organs on the palps 

 and first pair of legs of Galeodes, described by Bertkau {see Natural 

 Science, No. i, p. 53), are independently described by Gaubert, who 

 regards them as possibly auditory. The varying functions ascribed 

 to such organs by different observers show how much we still have to 

 learn of the life of Arthropods. 



The structure of the appendages and their muscles in the various 

 orders of Arachnids is described in great detail, and the homology of 

 their joints carefully worked out ; the attachment of the muscles is 

 of great value in this respect. According to Gaubert, the limb of an 

 Arachnid has three main divisions : a proximal part, directed upwards, 

 and consisting normally of coxo-, basi-, and meropodite (coxa, 

 trochanter, and femur), a horizontal part, sometimes of a single joint, 

 sometimes divided into two, carpo- and propodite (genua and tibia), 

 and a distal downwardly-directed part, the dactylopodite, which is 

 also sometimes divided into two (meta-tarsus and tarsus). An extra 

 division may be developed in any of these three parts of the limb ; in 

 the spiders and harvestmen the horizontal part is divided into genua 

 and tibia, permitting lateral motion ; in the Solfugidea and pseudo- 

 scorpions there is an extra joint between the trochanter and the 

 femur ; while in the scorpions the distal part of the limb is divided 

 into three joints, the horizontal part remaining undivided. It thus 

 appears that, although the limbs of a spider and a scorpion each have 



