SPINNING APPARATUS OP GEOMETEIO SPIDERS. 29 



The Spinning Apparatus of Geometric Spiders. 



By 



Cecil ITarburton, B.A., 



Christ's College, Cambridge. 



With Plate V. 



The familiar circular snare constructed by the " geometric*^ 

 spiders has always been an object of interest to naturalists^ but 

 it is remarkable how little has been known until lately of the 

 highly complicated organs which compose the spinning apparatus 

 of these animals. 



Thanks mainly to the labours of Blackwell,i Emerton,^ 

 Bertkau,^ and lastly Apstein, a tolerably complete knowledge 

 has now been obtained of the structure and general arrange- 

 ment of these organs. 



Apstein^s excellent paper,"* recently published, contributes 

 much that is new and valuable, and fairly represents our 

 present knowledge of the subject. Recent researches, however, 

 have led me to dissent from some of that author's conclusions 

 as regards the functions of the various spinning glands, con- 

 clusions based upon evidence for the most part too indirect to 

 be entirely satisfactory. 



Before discussing this matter, some description of the 



' "On the Maramalse of Spiders in Spinning," 'Trans. Linneau Soc, 

 London,' 1839, vol. xviii, pt. ii. 



2 'The Structure and Habits of Spiders,' Boston, Cassino & Co., 1883. 



^"Cribellum und Calamistrum," 'Archiv fiir Naturgeschichte,' 1882, 

 p. 316. 



* " Bau und Function der Spinnendrusen der Araneida," 'Archiv fiir Natur- 

 geschichte,' 1889, p. 29. 



