SPINNING APPARATUS OP GEOMETRIC SPIDERS. 



31 



Acinate. The first three kinds are few in number and of large 

 size, extending throughout the greater part of the abdomen. 

 The piriform and acinate glands are minute and numerous, 

 and are closely grouped together immediately above the 

 spinnerets. 



Their exact arrangement is important and may be summarised 

 as follows : 



There are two pairs of AmpuUaceal glands (fig. 3) debouch- 

 ing on the anterior and intermediate spinnerets re- 

 spectively on the inner side. 



There are three pairs of Aggregate glands, their three 

 outlets on each side being situate upon the inner surface of 

 the posterior spinneret. 



There are three pairs of Tubuliform glands, two opening 

 on the inner side of the posterior spinnerets, and one upon the 

 outer surface of the intermediate spinnerets. 



The above glands are comparatively large, and their ducts 

 terminate in distinct tubular prominences. 



There are about 200 Piriform glands, all connected with the 

 anterior spinnerets, where their ducts terminate in hair-like 

 tubes. 



Finally, there are about 400 Aciniform glands, each 

 posterior and each intermediate spinneret bearing the hair-like 

 terminations of about a hundred ducts. 



Or thus, tabulating for one side only : 



The question naturally arises as to the different functions 



