THE MAXILLA OF TEGENABIA DOMESTICA. 157 



wards towards the mouth. I am inclined to think that these 

 glands have a function equivalent to salivary ; and in many species 

 of the Linyphiidse, Theridiidse, Salticidse, and Epeiridse there are 

 similar organs, but distributed at the side of the maxillse close to 

 the mouth in a cup-like cavity, as seen in the accompanying fig. 4, 

 from an Epeira similis, Blackw. 



A peculiarity of the ducts is that in many species they become 

 ehitinous (fig. 4) ; and this is common in adults, so that it cannot 

 be considered the result of a condition preceding a moult. 



Fig. 4. 



Chitinous gland-opening on maxilla of Epeira similis {S), as seen from 

 outside of maxilla, with one chitined-gland attached, X 200. 



In the Tegenaria domestica, Blackw., and also in other species, 

 the number of these glands, together with the integumental 

 channels, increases with age. I found only one aperture on each 

 maxilla of the first exuvium of ten of this species and two on 

 the second. A young one which last year I kept in confinement 

 gave the following results, viz. : — 



Date of exuvium, Number of gland- 

 1879. openings. 



]5thMay Woodcut fig. 5, A 13 



9th June „ B 21 



1st August „ C 31 



21st September ... „ D 46 



In the diagrammatic woodcut (fig. 5, C, D, E, and E) the relative 

 positions on each exuvium are indicated ; and it will be seen that 

 the number on each maxilla is the same, though the distribution 

 is not. Unfortunately this Spider was allowed to escape in 

 December, so that I cannot give more figures ; but fig. 5, Q-, 

 represents eighty gland-openings on an adult Tegenaria domes- 

 tica (female), while in others I have found as few as sixty. 



These remarks are the result of an investigation which was 



