I:^TEST1NAL TRYPANOPLASMAS OF FISHES. 
181 
of flagella, and with a large, rounded, vacuolar kinetonucleus 
and a small troplionucleus. Whether this process may be 
regarded as the commencement of encystation I am not at 
present clear. 
ly. Heteromita dahlii (Apstefn) ; Trypanoplasma ventri- 
coLi (Keysselitz) ; Diplomastix dahlii (Mobius). 
This form appears to have had a remarkably chequered 
history. It was first discovered by Dahl on March 31st, 
1887, and a short account of it was given by Mobius in his 
Bruchstucke einer Infusorien Fauna der Kieler Bucht 
under the name of Diplomastix dahlii. He described it as 
a spindle-shaped animal with a flagellum double as long as the 
body at either pole. The next mention of this flagellate that 
I can find is in Keysselitz’s paper on Generation und Wirts- 
wechsel von Trypanoplasma Borreli^^ (p. 37). Keysselitz 
apparently had overlooked Mobius’s work, since he calls the 
animal Trypanoplasma ventriculi. He gives three 
figures of the animal under this name, and points out that 
the blepharoplast is very frequently split into two pieces. 
Apstein, in his very valuable paper onCyclopterus lumpus, 
again gives a short description of this flagellate under the 
name of Heteromita dahlii, and points out that the name 
Diplomastix is untenable since the flagella both arise from 
the anterior pole. 
Out of 101 Cyclopterus which Apstein examined he found 
that 98 were infected. He described the movements of 
the active forms in some detail, and also some rounded forms 
which he regards as cysts. He did not succeed in finding 
any dividing forms, and he draws attention to an interesting 
mould which is found in association with the flagellates on 
the stomach-wall. As this animal shows so many points of 
difference from any other flagellate, free-living or parasitic, 
of which I have been able to find a description, I have 
decided to retain for it ApsteiiTs name Heteromita dahlii. 
In life the animal swims actively, keeping its posterior 
