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Herpetomonas luciliae n. sp. 
The reverse process takes place when the cell is on the ‘ up-grade/ the 
volutin being dissolved and resecreted by the protoplasmic basis of the 
nucleus, blepharoplast, and flagellar apparatus, respectively. 
The process is familiar in certain jflaut-cells, such as Spirogyra, in 
which the carbohydrate metabolism is similar. 
The pi’esence of volutin has been shown by Nuttall (1910), aud by 
Hindle (1910), to be associated also with degeneration of the cell, but 
in this Herpetomonas the most vigorous parasites are seen to contain 
the most volutin granules, or chromidia. 
Summary and conclusions. 
1. The parasite described inhabits the alimentary tract of two 
species of Lucilia. In addition it has a resting stage—the ‘cyst’— 
wdiich is passed in the voided excrement of the insect. 
2. When the cyst is ingested by a fly it grows in length and 
becomes flagellated in the ‘ crop ’; in the midgut it greatly elongates 
and multiplies rapidly by division ' in the hindgut it first shortens, then 
becomes spherical, and finally oval and cyst-like, meanwhile losing its 
flagellum. 
3. The cysts measure 3 p, the fully flagellate forms 20 p, in length. 
4. The cysts possess a cytostome and cytopharynx, the functions of 
which are probably nutritive. 
5. The flagellum consists of two parts (i) a cytoplasmic part, which 
probably subserves the power of movement and which I therefore propose 
to call the kinetoplasm, and (ii) a thread of chromatin secreted by the 
rhizoplast. 
6. The function of the chromatin in the flagellum is probably to 
sustain a filamentous form. 
7. The nucleus divides by a definite process something akin to 
mitosis. 
8. The chromidia serve as reserve material for the supply of 
chromatin in the cell. They are secreted probably by cell-plastids. 
9. I propose the name of this parasite be Herpetomonas luciliae, 
and that the genus Herpetomonas should be defined so as to include the 
forms described as Leptomonas. 
