RESEARCHES ON THE CILIO-FLAGELLATA. 113 
careful observations, though I must confess that the ventral 
aperture in the test becomes somewhat inexplicable if it is not 
to be looked upon as an ingestive area. Still, there can be no 
doubt that if the cilio-flagellata were an isolated group, Bergh’s 
researches would oblige us to consider many of them as 
indubitable plants, and it is only comparative morphology which 
forbids this view of their affinities. They are so closely allied, on 
the one hand, to the Flagellata, many of which possess the most 
undoubted animal characteristics, and on the other, to the 
Ciliata, which no one would dream of considering as plants, that 
their systematic position must remain unaltered, and they 
must simply be taken as another and very striking instance of 
the impossibility of drawing anything like a hard and fast line 
between the animal and vegetable kingdoms. 
As to the systematic arrangement of the group, Bergh 
dividesit into two families, one of which—the A dinzda—contains a 
single new genus and species, Prorocentrum micans ; while the 
other—the Dzuzfera—contains three sub-families and eleven 
genera. | 
Prorocentrum, discovered by Bergh, is interesting as forming 
the nearest ally of the group to the flagellata. It has an oval 
compressed body, with both flagellum and cilia at the anterior 
end, and possesses neither transverse nor longitudinal grooves. 
Its membrane consists of two valve-like moieties. 
Among the Duzuzfera, the first sub-family, Dzxophyida 
approaches most nearly to Adinzda, having the transverse groove 
near the anterior end. The second sub-family, Perzdinida, 
contains the typical genera, Perzdinium, Glenodinium, Ceratium, 
&c., and is distinguished by having the transverse groove about 
the middle of the body. The third and last sub-family, 
Gymnodinida, contains three genera, distinguished by the 
entire absence of a membrane. 
It is these naked genera which approach, in a remarkable 
way, to the ciliata. One species of Gymnodinium, for instance, 
exhibits in the ectoplasm the curious muscle-like myophan- 
striz so characteristic of Paramecium, Spirostomum, and other 
ciliate forms. The curious Polykrikos was considered by UI- 
janin as a turbellarian larva, and by Biitschli was placed among 
the Ciliata, in spite of its long flagellum. Bergh considers it 
as a true cilio-flagellate, distinguished by having several, 
instead of one, transverse ciliated grooves. It is also re- 
markable for possessing trichocysts, which, as figured by 
Bergh, have the closest resemblance to the thread-cells of 
Ccelenterata. : 
I cannot but think it a matter for regret that Bergh should 
be so permeated with “ Haeckelismus” as to adopt the custom 
of calling his classification a phylogeny. The method of 
showing affinities by genealogical trees or other diagrams is a 
convenient and commendable one, but to call a natural arrange- 
ment of a group, based upon the study of recent forms only, a 
phylogeny, is a misuse of language, and gives a fallacious, 
