SPIDEES AND MITES. 253 



blind sac in tlie last joint but one of the limb ; and 

 then follow it up to its junction Avith a great vessel 

 wMcb runs longitudinally through the trunk, of which 

 all the vessels that permeate the limbs are branches, 

 and whence the circulating globules all proceed. Tliis 

 great vessel is the stomach and this circiilation is the 

 provision for dispersing the nutritive properties of the 

 food to all parts of the system. There is in these hum- 

 ble and simply organized animals no proper blood, or, 

 at least, none included in a system of arteries and 

 veins ; but the products of digestion are carried to the 

 most distant parts of the body, through this extraordi- 

 nary development of the stomach or intestine (both in 

 one,) and through this series of blind canals, by means 

 of their own irregular contractions, aided by the mus- 

 cular movements of the body and limbs. 



Tou would scarcely forgive me if I took no oppor- 

 tunity of showing you the Cheese-mite, that first object 

 of wonder to every child that looks through a magnify- 

 ing glass. And no place so suitable for its introduc- 

 tion, as in connexion with its cousins, the Spiders and 

 Harvestmen. Well, fortunately, we need not search far 

 for specimens ; for here, in the cavity of this almost 

 defunct skeleton of a cheese, we can find as many mil- 

 lions as you can reasonably desire to select from. Here 

 is a fat one ; we'll take him. 



Tou see with a pocket lens that it has a plump, pol- 

 ished oval body, of a pellucid Avhite hue, and eight 

 short red legs ; but for more than this we must go to 

 the tube. Look at him now, as he lies on his back, 

 helplessly sprawling and throwing his feeble legs about, 

 in the live-box. 



His oval body is divided by a transverse furrow into 



