as Infusoria flagellata. 203 



The contractile vesicles {cv) are two or three globular bodies, 

 which, in appearance, position, 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 {2^^)' When not filled by the 

 head (fig. 32, i) of the animalcule, the neck and the sharp 

 margin (c^) of its aperture may be clearly distinguished from 

 the collar {b) 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 joins 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 apertui-e. 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. Salpingoeca ampJioridium, no v. sp. PI. VI. figs. 37-37*^. 



Although this species bears a strong resemblance to S. ma- 

 rina (§ 8) , there are several prominent points of difierence 

 between the two. 8. amphoridium is a freshwater form, and 

 appears especially to frequent old specimens of Zygnema and 

 other filamentous Algge. 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 8. 

 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^, i) with a gentle motion, and apparently in search of 

 something. 



The hody is grey or greenish yellow in colour, which fades ' 



