GENUS PHI A UN A . 519 



prolongation; in two instances this part, Figs. 26 and 27, is shown to project con- 

 spicuously beyond the oral fringe of cilia, while in the other, Fig. 25, these cilia 

 seem to issue from the apical extremity itself, an aspect which would necessarily 

 result from the withdrawing inwards of this structure. The TricJwda ambigiia of 

 O. F. Miiller * would seem to agree with this t)-pe in the flattened screw-like contour 

 of the posterior region of the body, and is possibly identical with it. At the same 

 time the body of Miiller's species would appear to have a more elongate and 

 vermiform shape, and it is apparently not capable of contracting into a globular form. 

 Like the present species, it is an inhabitant of salt water. 



Genus III. PHIALINA, Ehrenberg. 



Animalcules free-swimming, subcylindrical or flask-shaped, slightly- 

 elastic, narrowest anteriorly, a portion of the apical region separated from 

 the rest of the body, as in Traclidophyllum and Lacryviaria, by a circular 

 groove, and bearing a circlet of longer, usually reflected cilia ; the oral 

 aperture situated in the anterior annular groove, and not terminal as in the 

 two last-named genera ; cuticular surface finely and entirely ciliate ; 

 contractile vesicle single, adjacent to the postero-terminal anal aperture. 



With the exception of the antero-lateral, instead of apical position of the mouth, 

 the animalcules of this genus correspond essentially with those of Latrymaria, and, 

 unless the e.xact position of this aperture is seen and determined, are liable to be 

 confounded witli them. 



Phialina vermicularis, Ehr. Pl. XXVII. Figs. 36. 



Body subcylindrical, ovate or pyriform, narrowest anteriorly, two and a 

 half times as long as broad, the apical portion in advance of the annular 

 furrow short and broadly cylindrical, its anterior margin truncate and bear- 

 ing a single circlet of cilia, these cilia usually directed backwards ; oral 

 aperture opening on the annular furrow ; surface of integument smooth, 

 finely and entirely ciliate ; contractile vesicle single, spherical, postero- 

 terminal ; endoplast ovate, subcentral, obliquely directed. Length of body 

 1-240". Hab. — Pond water. 



The lateral position of the mouth of this animalcule has been very clearly indicated 

 by Ehrenberg, but, as intimated by Claparfede and Lachmann, the figure referred to 

 most probably depicts an example observed at the moment of engulfing food, the 

 organ at other times being difficult to recognize. By Ehrenberg and various earlier 

 wTiters the cuticular surface of Phialina, as in the case of Lacrymaria, Trachdocerca, 

 and other forms, is described as being entirely glabrous. More recent observation, 

 assisted by the emplojTnent of superior magnifying lenses, has, however, determined 

 the presence of fine cilia throughout its whole extent The aspect of Phialina 

 vermicularis, with its reflected anterior circlet of larger ciUa only visible, has been 

 not inaptly compared with that of a minute Echinorhytuhus. 



Doubtful Species. 



Tht Phialina viridis of Ehrenberg, PI. XXVII. Fig. 37, is suspected by Claparfede 

 and Lachmann to be a coloured variety only of P. vermicularis ; according to 

 Ehrenberg's figures, however, the body also is differently proportioned, the posterior 



' Animalcula Infusoria,' p. 200, pl. xxviii. figs. 11-16, 17S6. 



