98 CIENKOWSKl's REMARKS ON DR. STEIn's 



every endeavour he was never able to keep the emhryo long 

 enough in the field of view. "The only proof^ therefore, 

 would exist in the extraordinary resemblance of the motile 

 embryo, in form, ciliation and movement, to the detached 

 gemmated embryo of Vorticella microstoma." "^ 



My own researches on Podojjhrya have led to the follow- 

 ing results : 



Podoplirya fixa, Ehr., occurred in great abundance in an 

 infusion containing multitudes of StylonycJiia mytilus and 

 S. pustulata. The spherical body was furnished on all sides 

 with capitate retractile rays, and fixed on a peduncle, or 

 free. The peduncle was enlarged on the free extremities, 

 straight or slightly curved, and it was as long or longer than 

 the body. 



The contents of the body were in most instances more or 

 less opaque, coarsely granular, and enclosed a round con- 

 tractile space, and an oval, straight or curved nucleus ; 

 which coidd be perceived only in those individuals in which 

 the contents were fluid. I could not perceive any mem- 

 brane surrounding the body. Nearly every specimen of the 

 Stylonychice was infested with one or several PodophrycB. 

 In proportion as the body of the Stylotiychia diminished in 

 size and broke up^ did the colour of the PodophrycB become 

 deeper and deeper, and their size increase. In many indi- 

 viduals, fed in this way, a shallow cii'cular depression might 

 be seen surrounding the body equatorially (fig. 1). In 

 about half an hour this annular constriction had advanced 

 to complete transverse fission (pi. VII, figs. 2, 3). About ten 

 minutes afterwards the upper segment had assumed an 

 elongated form, was more cylindrical, a little indented in the 

 middle, and rounded at each end; and at the extremities 

 slight oscillations to the right and left could be perceived 

 (fig. 3). A transverse and, freqiiently, curved nucleus was 

 visible in the fiuid contents, and a lateral contractile space 

 could be clearly distinguished in the upper parts. The 

 vibrations increased in frequency and force until the segment 

 became wholly detached and escaped. During the process 

 of division both segments were furnished with tentacles ; 

 but when the oscillations of the cylindrical portion com- 

 menced, very fine and short cilia might be seen, though with 

 difficulty, vibrating on the free end, the tentacles at the 

 same time being retracted, and remaining visible only on the 

 posterior segment. I now followed uninterruptedly the 

 movements of the liberated segments. They moved for the 



* Stein, 1. c, pp. 1()7, 108. 



