The Structure and Habits of Spiders. 93 



hard appendages to support and guide the pal- 

 pal organs when the latter are thrust into them. 

 These parts, like the palpal organs, furnish con- 

 venient marks for distinguishing species. The 

 spermathecae, E, vary but little in shape in 

 different spiders ; but the tubes H and D are 

 often lengthened, and twisted into shapes near- 

 ly as complicated as those of the palpal organs. 



Fig. 50. 



Fig. 50 is the epigynum of a small Theridion, 

 where the arrangement of parts can be very 

 distinctly seen. E, E, are the spermathecae ; 

 H, H, the tubes opening into the oviduct ; and 

 D, D, the tubes opening outward. Fig. 51 is 

 the epigynum of another closely allied species, 

 where the tubes D, D, are very much elongated 

 and twisted up, corresponding to the long dis- 



