EVOLUTION 



347 



Lankester (1904) has convincingly demonstrated. The 

 abdominal limbs of Thysanura (Fg. 52, B) and the rudiments 



Fig. 79. — a, mandible {m, molar area) ; h, hypopharynx (Ji) and 

 superlinguae {$) of Mayfly Larva {Heptagenia). X 12. After Vayssiere 

 {Ann. Sci. Nat. Zool. xiii. 18S2). c, mandible ; d, hypopharynx and 

 superlinguae (the left superlingua displaced) of Bristle-tail (Petrobius). 

 X 30. e, mandible ; /, hypopharynx and paragnaths (p) ; and g, maxil- 

 lula of Isopod Crustacean (Ligia). X 12. After G. O. Sars (Crustacea 

 of Norzmy, ij, 1899). 



