PARADISE KEY SAFFORD. 



391 



an interesting little creature, actively climbing among the submerged 

 stems and leaves of plants, breathing in and expelling water by 

 means of a double-barreled siphon. 



Of greater economic importance than the i 



large marsh snails above mentioned are the 

 crawfishes of the Everglades, which are eaten 

 in great quantities by many marsh birds, espe- 

 cially by white ibises and blue herons. Speci- 

 mens collected in the immediate vicinity of 

 Paradise Key (pi. 37) were identified by Mr. 

 W. L. Schmitt of the United State National 

 Museum as Cambarus fallax Hagen. 



The centipedes and scorpions of Eoyal Palm 

 State Park are represented in the writer's col- 

 lection by a single species each. The first, 

 identified by Mr. 0. F. Cook as Theatops 

 postlca, is interesting on account of its pe- 

 culiarly hooked and thickened last pair of legs. 

 Its bite, though poisonous, is not dangerous. 

 The scorpion identified by Dr. Nathan Banks 

 as Centrums gracilis, like all of its allies, has 

 pincerlike palpi resembling the claws of a 

 crawfish, and a long tail terminating in a poison 

 sting (pi. 38). Perhaps the most interesting 

 feature of its anatomy is a pair of minute, di- 

 verging, comblike organs borne on its ventral 

 side just behind the last pair of legs (fig. 14). 

 The function "of these little combs is not yet 

 understood. An ally of the scorpions, which 

 may be regarded as intermediate between them 

 and the spiders, is the giant whip scorpion, 

 Mastigoproctus giganteus, shown on plate 38. 



Its enormous palpi suggest the branching mandibles of a large stag 

 beetle. In the scorpion the front legs are the shortest pair, while in 

 the whip scorpion they are greatly elongated; 

 but the greatest difference is in the tail, that 

 of the whip scorpion being entirely devoid of 

 a sting. Even the fangs of this ugly creature, 

 so much dreaded by the natives wherever it 

 is found, are said by Doctor Banks to be de- 

 void of poison. When attacked it emits an 

 acid, vinegarlike odor, from which the name vinaigrier has been 

 given it by French Creoles in the Antilles. 



Fig. 13- 



SXAIL, 



prcssa, 



WATER 

 SIZE. 



Eggs of marsh 

 Ampullaria de- 

 ox STEM OF 



plant. Nat. 



Fig. 14. — Comb-like or- 

 gans or scorpion, Cen- 

 trums gracilis. Their 

 function is unknown. 



