306 Transactions of the Society. 



Henneguy, " the animalcule come out or send a lobe out of the 

 shell .... and I don't think the fact to be possible, given the 

 narrowness of the aperture and the form of the animal." 



We have then three Follicnlinx (and all of them very likely 

 F. holtoni) spoken of as belonging to fresh- water ; and I think we 

 might add a fourth to the list. Zacharias, when treating of 

 Stentor cceruleus, writes : " On the 10th of October I found a single 

 specimen of this last species, in a flask-shaped cyst (fig. 12), which 

 had an aperture at the elongated anterior end. The cyst itself, as 

 well as the animalcule, was of a pale bluish colour. There was no 

 kind of stopper nor any operculum at the aperture of the cyst." 

 Now according to this description, and also to the figure, Zacharias 

 had very likely seen F. holtoni. 



I was therefore rather astonished upon ascertaining quite 

 recently that all the previous statements about a fresh-water type 

 were considered due to defective observations. " The genus 

 FoUiculina is not represented in fresh- water," says Sahrlage (" Arch, 

 f. Protistenkunde," vol. 37, fasc. 2, p. 144, 1916), and further, 

 p. 145: "Kent claims to have found F. holtoni in fresh-water; a 

 very doubtful species " ; further still : " F. holtoni .... can hardly 

 be recognized as belonging here ; more likely it is a badly ob- 

 served Vaginicola, whose shell, according to Kent himself, is just 

 the same. The same might be said of the 'shell-inhabiting 

 Stentors ' of Barrett, so that in fact only marine Folliculinie are 

 known to have been found to this day." 



Now these rather surprising statements, as well as some others 

 of a different nature, which went against wliat I had seen, induced 

 me to a further study. Although it was now the 12th of December 

 the pond was not frozen over, and a few leaves of the water-lilies 

 were still floating about, from the under-surfaces of which a sufficient 

 number of Folliculinsd, in perfect condition, were gathered for 

 study. 



The following pages are the result of these December obser- 

 vations, which, in fact, were protracted to the 15th of January so 

 far as a few specimens were concerned. 



But before going into the subject, I wish to emphasize the fact 

 that all my observations have been made on isolated animals, 

 kept under the cover-glass in excavated slides. This method of 

 study cannot be too highly recommended, for it allows of facts, 

 which might otherwise remain doubtful, being established with 

 certainty. Wright, for instance, and also Claparede and Lachmann, 

 supposed that certain vermiform bodies which they had seen 

 swimming about might represent a larval form of F. elcgans. 

 Later on, these same vermiform bodies were several times met 

 with, and finally described by Daday as Lagynus ocellatus. Sahrlage 

 considers them still as representing an independent genus; but if 

 the specimens had been observed after isolation in a drop of clear 



