Folliculina holtoni (S. Kent). 315 



according to their own statement, the same Infusorian, which they 

 give as a young form of Freia elegans, had been previously observed 

 by Lieberkiihn and by Wagner at Wismar on the Baltic, without 

 these authors seeing in it any relation to Folliculina. Later on 

 Daday described it from the Gulf of Naples under the name of 

 ' Lagynus ocellattis,' and regarded it as a peculiar species close to 

 Lacrymaria, yet without leaving out of account the ' interesting 

 thought' of some relation in origin with the genus Folliculina. 

 Levander more recently saw it again in the Baltic, found the nucleus 

 most of the time oval, but also more rarely chaplet-like with five 

 beads, without perceiving, however, any new argument for a relation 

 with Folliculina, which relation he considers as very improbable in 

 itself. And yet the mistake has continued to our own time. ..." 



There was no mistake in fact ! The transformation is certain, 

 and must even be considered as of frequent occurrence. I was able 

 to observe it on three separate occasions, and each time on 

 specimens which had been isolated on excavated slides, and had 

 subsequently left their envelope behind, two of them on the third 

 and fourth day, and the last after thirteen days. 



The first indication of the transformation is the retraction of 

 the lobes ; the whole of the peristome apparatus grows more and 

 more indistinct, the vestibulum disappears, and finally no trace is 

 left of any structure. The animalcule has now got the shape of a 

 rather elongated egg, which rests with its posterior extremity at 

 the bottom of the shell.* 



The anterior extremity looks at first quite smooth, but very 

 soon there appears a terminal crown of cilia, or rather pectinellpe, 

 which moving slowly at first gradually become more and more 

 active. At the same time, the ordinary cilia, which cover the 

 whole body, become more and more distinct, and at last move 

 rapidly. 



The animalcule is now ready for leaving the shell, and it may 

 be certain that here, as in other Ciliates (Cothurnia, etc.), its exit 

 is very quick, though I was never able to verify the fact, being 

 ahvays absent at the time, and only finding on my return an empty 

 shell with a cluster of green matter left at the bottom, and at some- 

 distance the former tenant swimming about rapidly. 



The little vermiform being (fig. 10), about 160 /a in length when 

 fully extended, and 40 fj, in breadth, bears an anterior vibratile 

 crown, and, along the body, lines of cilia which move rapidly, and 

 are much more efficient than the croM^n as a means of locomotion. 



* The transformation inside the body is very difficult to follow. I was best 

 able to distinguish the details in a specimen (fig. 7) that was found on December 30 

 quite naked among the " debris." Up to January 4 it remained quite healthy and 

 with expanded lobes, but on that day began reabsorbing its peristome. The 

 vestibulum remained a long time in sight (fig. 9), like a pale narrow scalariform. 

 ribbon, due to the remnants of the nearly vanished cilia. Reabsorption of all 

 parts of the structure seemed to take place simultaneously. 



