BOOKS ABOUT SPIDERS. 



Classification. — Thorell's "Genera of European 

 Spiders," in "Acta Regiae Societatis Scientiarum Upsa- 

 lensis," 1869, and Thorell's "Synonymes of European 

 Spiders," contain a complete history of the classification 

 of the spiders of Northern Europe, with references to all 

 the descriptions of genera and species, and remarks on 

 the use of names and groups by different authors. The 

 great resemblance between the European and North- 

 American spider faunae make these the most useful 

 books for American students. Simon's " Arachnides de 

 France," a work not yet completed, describes all the 

 spiders in France, and refers to descriptions of the 

 other European species. It contains tables by which 

 the genus and species to which any spider belongs can 

 be found by the use of a few prominent characters. 



A \ \ i « mv. — Siebold's " Anatomy of the I nvertebrata " 

 contains a good general account. Bertkau describes, in 

 "Traschel's Archiv fur Naturgeschichte," the mandibles 

 in 1S70, the respiratory-organs in 1872, and the sexual- 

 ins in 1875. Oeffinger describes the spinning-glands 

 in "Archiv fur Microscopische Anatomic," i860. 



Embryology. — Claparede, Utrecht, 1862, and Bal- 

 biani, in "Annales des Sciences Naturelles," 1872, de- 

 scribe the growth of the egg from segmentation to 



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