354 



THE AMERICAN NATURALIST [Vol. LV 



tion stages constantly found in which the arms are either 

 being regenerated, or " redifferentiated," or reduced, to 

 vanishing point. 



It is precisely the great development of the edges of 

 the funnel that makes the f olliculina an advance upon the 

 simpler state found in the stentors, so that the more 

 simple folliculinas are those with a peristome readily 

 referable to the stentor state, while the very highly dif- 

 ferentiated folliculinas with extremely long ligulate lobes 

 right and left from the edge of the funnel are the most 

 remote from the stentors. 



While in classification the relative amount of develop- 

 ment of these lobes is evidently of great importance, it 

 will require observation of many living specimens, as a 

 rule, to determine whether a given specimen has short 

 lobes from its present stage of development in the indi- 

 vidual life cycle or from its permanent place in the stage 

 of evolution from the stentor-like ancestor. On the other 

 hand, the presence of long ligulate lobes will at once de- 

 termine a high stage of individual and phyletic advance 

 and place the specimen in the highest group of anatomical 

 development. 



But until the possibilities of change of form in each 

 individual are known, and in the probable possession of 

 only poorly preserved specimens, the practical expedient 

 will be to adopt much of the procedure of Dons in mak- 

 ing use of the forms of the dwellings in the description 

 of what may for the present be regarded as species within 

 the group of Folliculinas. 



Relying, then, largely upon the bottles as indicative of 

 specific differences, in the American Folliculinas, so far 

 known, we may tentatively adopt the general subdivisions 

 of Carl Dons, retaining the genus FoUiculina for the 

 small, very wide sacs with short simple tubes. 



No form of this restricted genus has thus far been re- 

 ported from the American coasts. Whether such forms 

 are anything more than starved, depauperate or imper- 

 fectly developed Folliculinas may well be doubted. 



