occurred in approximately equal numbers and both were 
affected by the elongation which had occurred. The ef- 
fects were much more striking in the tunicate ears and 
especially so in the ear illustrated in Plate VIII which 
represents an extreme example of elongation. 
A study of this and similar ears reveals the real nature 
of the ear of maize more clearly than has ever been pos- 
sible by anatomical studies. It should be pointed out 
that these ears are not abnormalities in the sense that the 
normal course of development has gone drastically awry 
—they are not teratological phenomena. Instead, the 
normal potentialities of the ear, apparently always pres- 
ent, have been more completely developed than is usu- 
ally the case. This, in combination with the tunicate 
condition, has resulted in ears so elongated and stretched 
out that the individual nodes of the rachis and the ar- 
rangement of the spikelets upon them are clearly re- 
vealed, as illustrated by Plate [X.* There is apparently 
no essential difference between the structure of the ear at 
the base where it was completely enclosed in the husks 
and at the tip where it was completely free from the 
pressure and restraint exerted by the husks. There is a 
gradual transition, not an abrupt change, from one con- 
dition to the other. 
There are several definite and important conclusions 
to be drawn from these elongated ears of Guarany pod 
comm: 
Homologies. There is now no doubt, if there was 
doubt before, that the ear is the homologue of the central 
* The use of genetic characters in studying the nature of various 
structures of maize and its relatives offers important possibilities. The 
tunicate gene transferred to teosinte by repeated backcrossing fur- 
nishes a most convincing demonstration that the shell of the teosinte 
fruit is composed of a rachis segment and an indurated glume, as it 
has been described, and that it is the pedicellate spikelet which is 
aborted. 
[ 51 | 
