308 FOSSIL INSECTS. 



As far as we can argue from the analogy of living species, 

 the presence of large Scorpions is a certain index of the 

 warmth of the climate in which they lived ; and this indica- 

 tion is in perfect harmony with those afforded by the tropi- 

 cal aspect of the vegetables with which the Scorpion, found 

 in the Bohemian coal-field, is associated. 



SECTION IV. 



Fourth Class of Articulated Animals. 



FOSSIL INSECTS.* 



Although the numerical amount of living Insects forms 

 so vast a majority of the inhabitants of the present land, few 

 traces of this large class of Articulated animals have yet 

 been discovered in a fossil state. This may probably re- 

 sult from the circumstance, that the greatest portion of fossil 

 animal remains are derived from the inhabitants oi salt water ^ 



racteristic pincers on the right claw. Between this claw and the tail lies a 

 fossil carbonized Seed, of a species common in the Coal formation. 



The horny covering of this Scorpion is in a most extraordinary state of 

 preservation, being neither decomposed nor carbonized. The peculiar sub- 

 stance {Chitine or Elytrine) of which, like the elytra of Beetles, it is pro- 

 bably composed, has resisted decomposition and mineralization. It can 

 readily be stripped off, is elastic, translucent, and horny. It consists of two 

 layers, both retaining their texture. The uppermost of these (PI. 46', Fig. 

 6. a.) , is harsh, almost opaque, of a dark-brown colour, and flexible; the 

 under skin (PI. 46', Fig. 6. b.) is tender, yellow, less^ elastic, and organ- 

 ized like the upper. The structure of both exhibits, under the microscope, 

 liexagonal cells, divided by strong partitions. Both are penetrated at in- 

 tervals by pores, which arc still open, each having a sunk areola, with a 

 minute opening at its centre for the orifices of the trachea. Fig. 7. repre- 

 sents impressions of the nmscular fibres connected willi the movement o£ 

 tiie legs. 



» See PI. 46". Figs. 1. 2. Si. 4.— 11., 



