HISTORY OF ZOOLOGY 



29 



and then the cyclops-stage, because their ancestors were once fish-Iikc, 

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

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

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



Fig. 7. — Cyclops coronatus {A) and also its nauplius in lateral (B) and in ventral 

 view (C). /, head; II-V, the five thoracic, and behind the.se the five abdominal 

 segments; F, furca; i, the first, 2, the second, antenna;; 3, mandibles; 4, ma.xillx>; 

 5, maxilhpeds; 6-g, the lirst 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." 



