HISTORY OF ZOOLOGY 



29 



and then the cy clops-stage, because their ancestors were once fish-like, 

 perennibranchiate-like, nauplius- and cyclops-like. Here is expressed 

 a general phenomenon which Haeckel has stated under the name of 'the 

 Fundamental Law of Biogenesis.' "The development history (ontogeny) 



m. 



A 



FlG. 7. C\'djps coronatus (.4) and also its nauplius in lateral (5) and in ventral 

 view (C). 7, 'head; II-V, the five thoracic, and behind these the five abdominal 

 segments; F, furca; i, the first, 2, the second, antenna;; 3, mandibles; 4, maxilla-; 

 5, maxillipeds; 6-9, the first four pairs of biramous feet, while the rudimentary fifth 

 pair are hidden; au, eye; o, upper Up; e, egg-sacs; d, gut; m, muscle. 



of an individual animal briefly recapitulates the history of the race (phylog- 

 eny); i.e., the most important stages of organization which its ancestors 

 have passed through appear again, even if somewhat modified, in the 

 development of individual animals." 



