188 Miscellaneous. 
they are also not quite transparent, but coloured sulphur-yellow at 
the margin, though colourless elsewhere. 
The creature as it floats and rests in the water has the shape of a 
Roman T; the unpaired hmb is band-shaped in transverse section 
and thickened into a knob at the free end. In the latter is to be 
noticed a yellow opaque body which, when examined under the 
microscope, proves to be a Distomum, usually doubled up, lying in a 
cavity of the knobbed end, which is beset with rings of papille. 
The paired limbs of the T constitute leaf-shaped movable appendages. 
Others of these ‘“ sporocysts” rest on the bottom of the vessel, lying 
on the broad side, with the forks of the tail closed or open. The 
whole assemblage usually rises all at once from the bottom and 
swims actively about in the water, in the way that our gnat-larvee 
do, afterwards floating again in the water—with the knobbed end 
downwards—or sinking slowly to the bottom. 
As 1 had collected various species of snails in the same receptacle, 
my first task was to separate them, and I soon ascertained that our 
“ free-swimming sporocysts” are developed from Limneus palustris, 
var. corvus. Among fourteen specimens of this species one proved 
to be infected with transparent sporocysts (four others with rediz) 
measuring as much as 2 millim.* in length, in which, as was soon 
evident, our ‘ free-swimming sporocysts ” arise. Yet we have not 
to deal with this stage, but rather with gigantic Cercarie with 
torked tails, the bodies of which, the future Distomum, exhibit the 
usual relations, so long as the Cercariz are enclosed in the sporo- 
cyst which produces them. After the escape the body becomes 
retracted into a cavity which was previously distinguishable in the 
swollen commencement of the tail, and remains in this condition. 
These ostensible “‘ free-swimming sporocysts ” are therefore enor- 
mously developed Cerearia, and resemble Cercaria macrocerca and 
CO. cystophora, except that they are a furcocercous form, 
Unfortunately my endeavours at rearing the Distomum by feeding 
some goldfish with it, which in a few minutes had devoured over a 
dozen Cercarix, were not successful; I could not rediscover the 
flukes either in the intestine, the muscles, or the eyes. I intend, if 
I obtain some more fresh material, to repeat the experiments with 
other fish, since a direct development, ¢. ¢. with the omission of a 
second intermediate host, is very probable ; possibly birds also may 
play the part of final hosts. 
Until the question of the species is decided, the Cercaria may 
stand as Cercuria mirabilis.—Zoologischer Anzeiger, xiy. Jahrg., 
1591, no. 375, pp. 368, 369. 
* [The original has “em.” —TRANSL. | 
i 
