OCCURRENCE OF NUCLEAR DIMORPHISM IN HALTERIDIUM. 347 
It is true that the number of Trypanosomes is very small 
in proportion to that of the Halteridia, but the dispro- 
portion is largely reduced if the sexual forms of the intra- 
cellular parasites are left out of account; and, as I have 
mentioned, the great majority of the Halteridia are of the 
male or female type. It is probable that the Trypanosomes 
are reinforced in number from the indifferent Halteridia as 
a rule; and from the female forms only in exceptional 
circumstances, e. g. perhaps late in the season, if unable to 
become fertilised. I do not think it likely that the male 
individuals give rise to ordinary Trypanosomes at all. 
In some of my preparations very good examples of micro- 
Text-Fic. 13. 
‘ 
8; 
| ae 
f 
aia 
a b c 
Male gametes, from peripheral blood, left a couple of minutes 
before smearing. 0 is the least intensely stained, c the most so. 
g. Centrosomic granule. x 2500, 
gametes are to be found. These had, in life, freed themselves 
from the residual body of the gametocyte, were actively 
motile, and for all I know to the contrary were fully-developed 
male elements. hey have been examined under the best 
obtainable conditions. This is essential, since the width of 
these fine organisms is only from 5 to-7. Unfortunately, 
too, the gamete takes up the stain so intensely, that it is 
often difficult to differentiate sharply between the nuclear 
and cytoplasmic portions. The chief evidence of trypaniform 
structure which I hoped to obtain was, of course, the presence 
of an undulating membrane, as shown by Schaudinn in his 
schematic figure. I examined, particularly, deeply stained 
specimens, thinking the flagellar border, standing out from 
