596 BIOLOGY. 



The following have a short body, in which the abdo- 

 men predominates; thorax and head connate; nevermore 

 than four pairs of feet Acari, Scorpions, and Spiders. 



They likewise divide into two orders, like the Kracken. 



Order 1. Itumpfkrackenartige Langkole. 



3515. Body horny, tolerably cylindrical and uniform ; 

 feet mostly very numerous. 



Fam. 1. Salpoid, Spindelkobe. 



Only three pairs of thoracic feet, but still podoidal 

 appendages to the abdomen Podura, Lepisma. 



Fam. 2. Ascidioid, ScJmurkobe. 



Body cylindrical, with very many feet ; sexual parts on 

 the thorax Juli. 



Fam. 3. Cirrhopodoid, Bandkobe. 



Body band-shaped and depressed, maxillae perforate, 

 sexual parts placed posteriorly Scolopendrce. 



Order 2. Kopfkrackenartige Kurzkobe. 



3516. Body thick, mostly globiform; head and thorax 

 blended together ; only four pairs of feet. 



Fam. 4. Brachiopodoid, Acarides. 



Body rounded ; all three parts confluent ; usually only 

 two simple eyes. The Acari are mostly so small, that 

 their parts can only be distinctly seen through the 

 microscope. Their mouth is always very much arrested, 

 and has maxillae, which are in some cases adapted for 

 manducation, in others for suction. 



Fam. 5. Pteropodoid, Scorpions. 



Body tolerably cylindrical, and all three parts connate ; 

 palpi very large and forcipiform. 



Fam. 6. Sepioid, Spiders. 



Body rounded, head and thorax connate, abdomen 

 separate, mostly eight simple eyes. 



Their most remarkable organs are the four spinnerets 

 in front of the anus, which probably stand in the signifi- 

 cation of the renal organs, just as the material of the 

 Spider-threads does in that of the urine. 



The tracheae are but few in number, and expand into 

 lung-like vesicles. 



