82 TRAP- DOOR SPIDERS. 



perhaps where the mould is liable to fall in ; and thus 

 I account for the loose rough laminae of silk tliat are 

 always found projectin<^ from the outer surl'ace. These 

 are overlaid with other patches more and more ex- 

 tensive, until the whole interior walls are covered ; 

 after which the silk is spun evenly and continuously 

 all round the interior, in successive layers of very dense 

 texture, though thin. Under the microscope, with a 

 power of 220 diameters, these layers are resolved into 

 threads laid across each other and intertwined in a 

 very irregular manner ; some are simple, varying from 

 y-oVo- to ^ToVo of an inch in diameter, and others are 

 compound, several threads, in one part separate, being 

 united into one of greater thickness which cannot then 

 be resolved .... The mouth of the tube is com- 

 monly dilated a little, so as to form a slightl}^ recurved 

 brim or lip ; and the lid is sometimes a little convex 

 internally, so as to fall more accurately into the mouth 

 and close it. 



The thickening of the hinge by additional laj^ers is, 

 I think, accidental only, as, out of the many specimens 

 that I have examined, only one or two had such a 

 structure. In the neatest examples, the lid is of equal 

 thickness throughout its extent, agreeing also with 

 the walls for the first few inches of their depth," 



Mr. Gosse says that he possesses one specimen of 

 peculiar compactness, which differs from all the others 

 that he has examined in having " a row of minute 

 holes, such as might be made by a very fine needle, 

 pierced around the free edge of the lid, and a double 

 row of similar ones just within the margin of the 

 tube. There are about fifteen or sixteen punctures 

 in each series, and they penetrate through the whole 



