OCCURRENCE OF NUCLEAR DIMORPHISM IN HALTERIDIUM. 341 
often be seen in a few fields of the oil-immersion lens, 
particularly in liver-smears. A very large number of 
Halteridia have passed under my eye, but I have never 
seen the least sign of endogenous multiplication (schizogony) 
in any of the adult individuals in the red blood-corpuscles, 
i.e. never anything approaching the nuclear fragmentation 
and segmentation of the cytoplasm at the two ends, which 
was described by Labbé.! The minute forms do not arise, I 
am convinced, by the division of the large ones. 
Many of the Halteridia exhibit in regard to their nuclear 
TEXxtT-FIas. 1-3. 
9 
vo 
Female individuals of Halteridium. 1. From peripheral 
blood, left a couple of minutes before smearing. 2. From 
liver-blood; and 3, from peripheral blood (of living bird), both 
smeared at once. K. Kinetonucleus, or kinetonuclear element. 
T. Trophonucleus, or trophonuclear element. Fig, 1 x 2000; 
Figs. 2 and 3, x 2500. 
structure a condition which undoubtedly represents nuclear 
dimorphism. By the term “nuclear dimorphism ”’ is under- 
stood a characteristic separation of the nuclear material into 
two constituents, a larger body staining red with Romanowsky 
modifications, and a smaller one, which is much denser and 
stains much darker. These two nuclei, which I have distin- 
guished? as tropho- and kineto-nucleus respectively, are of 
regular occurrence in Trypanosomes and other parasitic 
1 * Arch. Zool. Exp.,’ ser. 3, vol. 2, p. 55, 1894. 
> “The Hemoflagellates,” ‘Quart. Journ, Micr. Sci.,’ vol, 50, p, 151, 
1906. 
