Pearl, Reactions of Limulus. 



i6i 



Tabular Resume of the Behavior of Liiiuilns in the Earliest 

 Stage of its Free Existence, and in the Adult. 



Respiratory 

 Moi'onents. 



Swimmiiii^ 

 Movements. 



Walking 

 Movements. 



Righting 

 Reaction. 



Burrowing 



%$ Reactions. 



Gi/statory 

 Reflexes. 



Temperatu7-e 

 Reflexes. 



' ' Gill-scraping 

 Reflexes of 

 Sixth Legs. 



' ' Cleaning " 

 Movements 

 of Gills. 



Embryo. Adult. 



Same in character in embryo and adult. 



Legs and gills both 

 beat rhythmically 

 and synchronously. 



(iills only beat rhythmically. 

 Legs held in fixed position. 

 Gill movements the same in 

 character as in the adult. 

 Control of swimming move- 

 ment poor immediately after 

 hatching. Improve with prac- 

 tice. 



Essentially the same in character in embryo and adult. 

 Not so well coordinated and directed in embryo as in 

 adult. Improve with practice in embryo. 

 Present from beginning but Definite, immedi- 



not well coordinated. Not as ately purposive reac- 

 definite in type as in adult. tion. 



Probably same in embryo and adult. 



Absent. 

 Absent. 



Complex and highly 

 coordinated. 

 Definite and pur- 

 poseful reflexes. 



Essentially the same in embryo and adult. 



Absent. 



Present (cf. Hyde, 

 loc. cit.) 



From this comparison it appears at once that, with a sin- 

 gle exception, all the items of behavior presented by the adult 

 are, in the case of the embryo, either entirely absent or pres- 

 ent in essentially the same condition as in the adult. In other 

 words, the embryo does not in general have simple types of be- 



