322 SCIENCE PROGRESS. 



dangerous to any larger creature which, snapping it up, 

 might break off the forked end of the bristle and receive a 

 possibly poisonous wound. On the other hand, birds have 

 actually been seen ^ attacking Galeodes, although the obser- 

 vations are hardly sufficient to warrant any definite conclusion 

 either way. Here again experiments are very desirable. 



The claws of this formidable Arachnid also deserve 

 mention ; they are as terrible, in their way, as are the jaws. 

 They are very long and curved, and their tips are movable. 

 A tendon runs up the hollow of the claw and bends the tip, 

 when needed, sharply round. This mechanism enables the 

 claw to be firmly anchored in the body of the victim. 



Galeodes stridulates when enraged, and possibly also 

 at periods of sexual ripeness. While watching a specimen 

 which, being confined, was in a " positively astounding 

 fury," Pallas heard the screeching sound which the animal 

 made by rubbing its jaws together. As far as I know, 

 there is no record of any one else having heard this sound, 

 but stridulating ridges have recently been discovered by 

 Hensen and claimed as such by him, although he was ap- 

 parently unaware that the sound produced by them had 

 been heard by Pallas. These ridges do not occur in all 

 species. Both Spiders and Scorpions are now known also 

 to stridulate ; the apparatus, however, seems to be different 

 in each group. This somewhat remarkable fact tends to 

 support the view of the present writer that these different 

 Arachnids cannot in any way be deduced from one another, 

 but are separate developments of some common ancestor. 



A few of the more noticeable structural features may 

 be briefly mentioned. The enormous jaws differ from 

 those of all the other larger Arachnids in being hinged on 

 to the front lateral edge of the exoskeleton. The hinge has 

 been formed secondarily out of a crumpling and folding of 

 the skin at the side, and is clearly an adaptation to the 

 great size, and to the powerful muscles of these limbs. The 

 chitinous infoldings forming these hinges give rise to the 

 peculiar areas on each side of the " head," which have given 



^ Distant, Nature, vol. xlvi. p. 247. 



