226 THE PATH OF DEGENERATIVE EVOLUTION 



some stages, and possesses all its thoracic appen- 

 dages (three pairs of jaws and five pairs of 

 ambulatory appendages). In this larval life the 

 exopodites of the second and third pairs of jaws 



Fio. 71. Erychtheus larvae of Stomatopoda. 



A, The youngest known Erychtheus larva : I V, buccal appendages well developed. 

 B, Young Erychtheus larva : I and II modified buccal appendages ; III V, degenerating 

 buccal appendages; VI VIII, segments devoid of appendages. C, Older Erychtheus 

 larva: I II, modified buccal appendages; III V, reappearing buccal appendages; 

 VI VIII, ambulatory appendages in course of formation. (After Claus, in Lang's Traite 

 cCanatomie comparee, vol. i.) 



atrophy. Shortly before hatching, the first pair 

 of jaws atrophies completely ; the two pairs of 

 antennae and the two posterior pairs of ambula- 

 tory legs become very degenerate. In the young 

 phyllosome stage these organs are rudimentary, 

 but in the older phyllosome larvae the first pair 



