26 o 
G. E. Coghill 
the so-called erratic movements may have only a trophic value. i 
As such they would be essential to the perfecting of movements, 
but would have no directive value in the development of responses. ] 
If, moreover, this hypothesis is valid for the ontogenetic origin 
and development of instinctive behavior it would seem plausible, l 
also, as a theory of phylogenetic development. Its application to ; | 
phylogenesis, though, would clearly be in opposition to the idea, \ 
which is accepted by various psychologists, that instinctive ' 
behavior has somehow been reflected back into the race from the j 
intelligent type, — or, psychologically expressed, that instinct is a i 
phylogenetic derivative of intelligence. For the latter hypothesis, I , 
am not aware that there is any direct, experimental proof, while we 
do see, in such vertebrates as Amphibia which admit of early I 
experimentation, instinctive behavior (locomotion) developing i 
directly out of the simplest known reflex. However, while we i 
seem to have a definite conception of the psychic parallel of the ^ 
former (instinct), the concept of the psychic parallel of the latter i 
is much less definite, and largely disregarded by psychologists, i 
Yet it would seem that in the ontogenetic developments of the 
psychic life of Diemyctylus there must be quite as definite a reflex ; 
psychosis concomitant with the earliest and simplest reflex as there 
is an instinct psychosis with the later instinctive behavior in the 
form, for example, of locomotion; for, although the neuroses of 
the simple reflex are evidently not as elaborate as are those of loco- 
motion, they are quite as definite in form. But, however this 
hypothesis of the relation of the instinct to the reflex may appeal to i 
the psychologist, an adequate knowledge of the behavior of Diemyc- 
tylus must take into account the origin and development of locomo- ' 
tion from the simple reflex; for this reflex represents the simplest 
known physiological unit of the somatic neuro-muscular system, 
or of the somatic ‘‘action system.” The relation of this unit to any 
of the more complex neuro-muscular processes is certainly an i 
essential factor in the problem of behavior, or of physiology in i 
the broadest sense. 
In presenting the mode of locomotion of the amphibian embryo i 
it is not my intention to antagonize the current explanation of the 1 
propelling factors of the swimming movement of fishes, ordinaril}/ i 
described as being, in effect, the same as that of a sculling oar. 
The latter explanation, so far as I am aware, is offered with refer- 
ence to the adult fish, and it might not apply to an embryonic or i 
