iS93-] 109 [Hyatt. 
liuckman and Bather gave the following ap])ro[»riate example 
from Beecher'^s ami my own researches. 
"Thus we would say that the Productidae attained their 
paracme in the Permian, when they were represented by the 
phylogerontic Strophalosia and Aulosteges; that the characters 
of the neanic and ephebic stages of Coroniceras trigo- 
natum are phylocatabatic" (here phylanagerontic). While 
granting the need of using this distinctive prefix for the periods 
of evolution in the phylum one is likely to become confused 
unless he fully understands the use of the word "phylum" as 
applicable to all grades of genetic series. Thus, in ordinary accep- 
tation of the tehn, a phylum may be the entire class or any sub- 
division of it, even a single genus, ])rovided the forms can be 
shown to be genetically connected. It has been employed in this 
way several times in this text after the names, species, genus, 
family, etc., the ammonoidal phylum or ordinal phylum, phylum 
of tlie Goniatitinae or sub-ordinal phylum, family phylum, and 
even a iihvlum of vai-ieties and individuals. 
Till-; C'vci.K. 
rliylmn expresses genetic connection, cycle the totality of the 
phenomena, whether morpliic or physiologic, wliicliare exhibited 
1)3' ontogeny or jiliylogeny. 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, metaplasis, and paraplasis of the individual; or one 
may describe the cycle as exhibited by the embryonic, nepionic, 
neanic, ephebic, and gerontic stages, or the cycle of the phylo- 
geny as exhibited by the corresponding stages of evolution 
designated by their appropriate prefix '"phyl." 
There appears to be real need of two terms under the head of 
i;ycle, one for ontogeny and the other for phylogeny. It is pro- 
posed to use in this way ontocycle or ontocj^clon for the ontogeny, 
meaning the cycle of the individual, and phylocycle or phylocyclon 
for that of the phyhxm. This will make it practicable to use the 
terms monocyclon or monocyclic, polycyclon or polycyclic, etc.. 
