ORDER TRACHEARI^. 497 



small, in the form of a keel, and is terminated by two barbed 

 threads, divergent, and placed each on a small articulation ; 

 the other pairs of feet are annexed to as many segments. I 

 have perceived a large stigma on each side of the body, be- 

 tween the first and second feet, as well as a cleft at the base 

 of the belly. The abdomen is ovaliform, and composed of 

 nine rings. 



We suspect that the ancients have designated these arach- 

 nides under the names of Phalangium, Solifuga, tetrag- 

 natha, &c. M. Poe has discovered a species in the environs 

 of Havannah ; but the others are proper to the hot and sandy 

 countries of the old continent. These animals run with ex- 

 treme swiftness, throw up their head, and seem to wish to 

 defend themselves, when they are attacked. They are reputed 

 venomous. 



Chelifer, Geoff. Obisium, /%., 



Have the palpi elongated, in the form of arms, with pincers 

 like a hand, and didactylous at the end. All the feet are 

 equal, terminated by two hooks, and the eyes placed on the 

 sides of the thorax. 



These animals resemble little scorpions deprived of a tail. 

 Their body is flatted, with the thorax almost square, and having 

 on each .side one or two eyes. 



They run fast, and often backwards or sidewa3's, like the 

 crabs. Roesel has seen a female lay its eggs, and assemble 

 them in a heap. Hermann, the father, says that these in- 

 dividuals carry them collected in a cushion under their belly. 

 He even thinks, according to another observation, that these 

 arachnides can spin. 



His son {Mem. apterol.) divides this genus into two sections. 

 Some {Chelifer, Leach) have the first segment of the trunk or 

 thorax, divided into two by an impressed and transverse line ; 

 the tarsi with a single articulation ; a species of stylet at the 



VOL. XIII. K k 



