;?02 The American Geologist. November, 1898 
The Cycle. 
Phylum expresses genetic connection, cycle the totality of 
the phenomena whether morphic <>r physiologic, which is ex- 
hibited by ontogeny, phylogeny, or the physiological phenom- 
ena alone. Thus one can describe the cycle of the phylum in 
its rise and decline, the epacme, acme and paracme as purely 
dynamical phenomena exhibited by the increase in numbers 
of forms, etc., or the cycle of the ontogeny as shown by the 
increasing complexity of the development and its decline, the 
anaplasis, metaplasia and paraplasis of the individual, or one 
may describe the cycle as exhibited by the embryonic nepi- 
onic, neanic, ephebic and gerontic stages, or the cycle of the 
phylogeny as exhibited by the corresponding stages of evolu- 
tion designated by their appropriate prefix "phyl." 
There appears to be real need of two terms under the head 
of cycle, one for ontogeny and the other for phylogeny. It is 
proposed to use in this way ontocycie or ontocyclon for the 
ontogeny, meaning the cycle of the individual, and phylo- 
cycle or phylocyclon for that of the phylum. This will make 
it practicable to use the terms monocyclon or monocyclic, 
polycyclon or polycyclic, etc.. to describe the number of cy- 
cles observed. Thus the ammonoids are polycyclic. the Arie- 
f Ida' are decacyclic, the genus Coroniceras is an incomplete 
monocycle. 
It is not necessary to defend these terms before students of 
bioplastology ; they will be tested and if convenient adopted. 
For the benefit of others it may be mentioned that the cycle 
is of all degrees of development in ontogeny. Thus Insecta 
are apt to stop at the ephebic period and in many other ani- 
mals there is a similar limitation. 
Those who try to find a complete cycle of metamorphoses 
in their own special linesof research will often be disappointed 
and probably question that it exists at all. Thus for several 
years I could not find any evidence of its existence among 
certain cephalopods, those having a primitive organization 
like Endoceras and Orthoceras, but I have since seen well 
marked senile stages in these shells. 
Stages of Morphogenesis. 
As remarked by Buckman and Bather, '"it is possible to 
trace the evolution of one character from its firsl appearance 
