TEETH ON CLAWS OF ADULT SPIDERS. 195 



5 in 10 = 50 per cent.; the posterior claw has a maximum con- 

 stancy of 40 per cent, having 4 teeth 4 times in 10. This method 

 was pursued throughout. Where only five specimens of a 

 species were examined the result was calculated to ten. On 

 the basis of these data the following conclusions were drawn. 

 Where percentages are cited they are percentages of constancy 

 and refer only to the superior claws. 



1. Claws having larger numbers of teeth show more varia- 

 tion in numbers than claws having a smaller number and this 

 holds for both sexes. The percentages of constancy for the 

 superior claws of male and female are as follows : Spcrmophora 

 52 per c&nt., Dictyna volupis 54 per cent., Epeira marmorea 59.5 

 per cent., Lycosa nidicola 62 per cent., Theridiuui tepidarionim 

 68 per cent. A glance at the tables will convince one that this 

 order will practically hold for the relative total number of teeth. 



The same result is more strikingly shown by the inferior 

 teeth. In Dictyna volupis, which has normally 4-5 teeth on the 

 inferior claw, there are 16 variations in 80 cases of both males 

 and females ; while Spermophora and Lycosa nidicola, which have 

 normally only I and o tooth respectively have only 3 variations 

 in 80 cases in the former case and i in 60 in the latter. 



Moreover, the superior claws, having many teeth, show many 

 times as much variation as the few-toothed inferior claw. 



2. The teeth on the claws of the first leg show least variation 

 in number, those on the third most. The percentages of con- 

 stancy are : First leg, 61.5 per cent.; second leg, 60.0 per cent.; 

 third leg, 57.0 per cent.; fourth leg, 58 per cent. 



3. The number of teeth on the claws of the female varies 

 slightly more than in the male, the percentages of constancy 

 being 58.0 and 59.75 respectively. The inferior claw gives the 

 opposite result, however, for here in the females there are 17, in 

 the males 19 deviations from the normal in 160 cases. A glance 

 at the tables will disclose a sexual dimorphism in the total num- 

 ber of teeth which may be greater in the male or in the female 

 or the same in both, according to the species. Thus by actual 

 count 5 females of Epeira marmorea have 318, 5 males 335 

 ungual teeth on the right side ; but 5 females of Lycosa nidicola 

 have 318 teeth as against 228 for 5 males; while 10 females and 

 10 males of Dictyna volupis have each 1,030 teeth exactly. 



