Pearl, Reactioiis of Liniuhis. 139 



cult of accomplishment. For some time before the present 

 piece of work was begun it was the opinion of the writer that 

 valuable aid in the analysis of the behavior of higher organisms 

 might be gained by following the plan of the morphologist and 

 studying the development in the individual of the characteristic 

 features of the behavior. Just as the morphologist studies the 

 ontogeny of an organ as an aid to the understanding of the 

 adult condition, so might the comparative psychologist study 

 the ontogeny of a reaction. It seemed reasonable to suppose, 

 in view of the close relationship which Jennings and others 

 have shown to exist between structure and type of behavior in 

 lower forms, that in higher forms the behavior would be sim- 

 pler in character during embryonic or larv^al life when the struc- 

 ture is simpler. Of course we know in a general way that this 

 is true; but does it hold in detail for single complex reactions 

 and reflexes ? So far as is known to the writer, very little 

 systematic work on behavior has been done from this point of 

 view, except on some of the mammals and birds (cf. notably 

 the work of Mills, Lloyd Morgan and Small). In these 

 forms the behavior has evidently a considerable psychical ele- 

 ment in it. It was with the idea of determining whether anything 

 of importance might be gained by studying the ontogeny of re- 

 actions primarily reflex in nature that the present piece of work 

 was undertaken. 



The form chosen for study was the king-crab Limulus 

 polyphemus. The reasons for this choice were two fold ; in the 

 first place, I was already familiar with the behavior and reac- 

 tions of the adult organism, and in the second place, Limulus is 

 a form in which the behavior is quite complex, and yet at the 

 same time the different reflexes are strikingly definite and ma- 

 chine-like in character. The adult Lhnulus is an almost ideal 

 form for physiological work, on account of its tenacity to life 

 after most extensive operations have been performed upon it, 

 and because of the definiteness of its responses. Something of 

 the complexity as well as the definiteness of its behavior can 

 be gathered from the excellent account which Patten ('93) has 

 given of the gustatory reflexes, for example. 



