Spiders' Web.— Mr. H. J. M. Underhill publishes in "Science 



and the mechanism by which it\s produced. He finds that of 

 the two to four pairs'of spinnerets or web- forming papillae pos- 

 sessed by spiders, the British species have at least three pairs. 

 The first, or upper pair of spinnerets, produce plain threads of 



