as Infusoria flagellata. 203 
The contractile vesicles (cv) are two or three globular bodies, 
which, in appearance, pene relative size, and rate of sys- 
tole, may be compared with those of Codosiga pulcherrima. 
On one occasion (fig. 30) they amounted to four (cv) in num- 
ber, and were arranged in pairs, one above the other. 
The calyx (c c!) usually has the form of a Florence flask, 
but with a very short, thick neck, which flares (c!) slightly at 
the aperture. It sometimes, however, is slightly pointed at its 
base where it joins the pedicel (pd). When not filled by the 
head (fig. 32,7) of the animalcule, the neck and the sharp 
margin (c!) of its aperture may be clearly distinguished from 
the collar () which rises just above them; but very frequently 
this discrimination is attended with a good deal of difficulty, 
because when the body presses closely at this point, it overlaps 
the margin in question, and obscures it. The pedicel (pd) is 
not much longer than the calyx, and jou the latter with little 
or no expansion. It is colourless like the calyx, moderately 
slender, of a uniform diameter from top to bottom, and appears 
to be solid and homogeneous in texture. Figure 32? repre- 
sents one of three bodies which were found in the midst of 
several living animals of this species, and which had every 
appearance of being the deserted calycles of the same, with a 
collapsed aperture. In the next species (S. amphoridium) the 
deserted calycles (fig. 37°) were found so numerous among 
those which were occupied, and moreover retaining the shape 
of the latter so perfectly, that there could be no doubt that the 
calyx is not only a separate organism apart from the body- 
wall, but also may be as readily vacated as that of Cothurnia 
or Vaginicola. 
§ 9. Salpingeca amphoridium, nov.sp. Pl. VI. figs. 37-37". 
Although this species bears a strong resemblance to 8. ma- 
rina (§8), there are several prominent points of difference 
between the two. SS. amphoridium is a freshwater form, and 
appears especially to frequent old specimens of Zygnema and 
other filamentous Alge. It is very common in such places, 
and lives in more or less crowded groups. Excepting the main 
part of the body, it is very transparent, but not so faint as S. 
marina. It varies much in size, even down to half that of 
fig. 37%, Like its marine congener it always occurs single, and 
never with a trace of a pedicel to the calyx (c c!). As a com- 
pensation for this, if one may use the expression, it has a long 
_ neck, which is frequently seen bending from side to side 
(fig. 37,7) with a gentle motion, and apparently in search of 
something. 
The body is grey or greenish yellow in colour, which fades 
