Glossary 



(Definitions with especial reference to spiders) 



Abdomen. The posterior division of the spider body, comprising 

 the pedicel and usually largely unsegmented saclike portion bear- 

 ing the spinnerets. 



Anal tubercle. The small caudal tubercle bearing the anal opening; 

 the postabdomen. 



Antennae. The segmented sensory organs often termed "feelers," 

 borne on the heads of insects, Crustacea, etc., but missing in all 

 arachnids. 



Appendages. Parts or organs (such as legs, spinnerets, chelicerae) 

 that are attached to the body. 



Arachnida. A principal division, or Class, of the air-breathing 

 arthropods, the arachnids, including the scorpions, mites, spiders, 

 harvestmen, etc. 



Arachnologist. One who studies the arachnids. 



Araneae. The ordinal name of all spiders; same as Araneida. 



Araneology. The branch of zoology that treats only of the spiders. 



Arthropod. The jointed-legged animals, such as centipedes, milli- 

 pedes, insects, crustaceans, spiders, scorpions, and many other less 

 well-known types; the members of the Phylum Arthropoda. 



Attachment disc. The series of tiny lines that serve to anchor the 

 draglines of spiders. 



Autophagy. The eating of an appendage shed from the body by 

 autotomy or otherwise. 



Autotomy. The act of reflex self-mutilation by dropping append- 

 ages; unknown in the arachnids. 



Autospasy. The loss of appendages by breaking them at a prede- 

 termined locus of weakness when pulled by an outside form; 

 frequent in spiders and arachnids. 



Ballooning. Flying through the air on silken lines spun by spiders. 



Book lungs. The respiratory pouches of the arachnids, filled with 

 closely packed sheets or folds to provide maximum surface for 

 aeration; believed to be modified, insunk gills. 



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