370 BOTANICAL GAZETTE [May 
in all of which it is a prominent character in the majority of their 
prosoplasmas. (2) The tendency toward the up-walled (“umwal- 
lungen”) condition. This is partially attained in the Acarina and 
Psyllidae, fully attained in the Aphididae, Coccidae, Itonididae, 
and is superimposed as the distal false chamber on certain galls 
of the Itonididae and Cynipidae. (3) The tendency toward the 
dehiscent type. This is much more restricted, appearing only in 
the Itonididae and the Cynipidae. (4) The tendency toward . 
appendicular structures borne by the galls. This tendency is 
almost confined to the Cynipidae. It has appeared in a weak 
degree in other groups, as in the Aphididae and in certain hickory 
itonids in which the gall base flares out into ill-defined processes, 
In the Cynipidae a great variety of appendages is found for 
which it is not possible to find homologues anywhere on the host 
plant. Many minor tendencies can be traced out in gall phy- 
logeny studies which may only be mentioned in this general 
paper. Among such are those toward certain forms, those toward 
certain orientations of tissues, those toward specializations with 
regard to certain chemical content (high tannin deposition, etc.), 
and those associated with the transition from the polythalamous 
to the monothalamous condition. 
Recapitulation data 
If zoocecidia are amenable to the same evolutionary interpre- 
tations as are used in the study of plant and animal parts, then 
voN Barr’s law should apply to the situation, and this is exactly 
what is found. Striking examples of recapitulation phenomena 
may be found in all the larger gall groups, yet, strangely enough, 
so far as the writer knows, no one has called attention to them or 
even to the possibility of the law applying in the zoocecidial field. 
The most fundamental fact in this connection is that all proso- 
plasmas in their ontogeny recapitulate the kataplasma stage. 
The initial stages of all prosoplasma galls (so far as known), 
which begin on partially differentiated host tissue, involve 4 
process of dedifferentiation; the tissue is thrown back into 4 
homogeneous condition (full kataplasmic state) out of which grows 
the new structure. Of course in those instances in which the larva 
