No. 639] 



AMERICAN FOLLICULINAS 



363 



The sac is fastened by secretion to some foreign body 

 and the animal lives sedentary till such times as it may 

 break loose from attachment of foot end to base of inside 

 of sac and then swim free to soon secrete another sac and 

 tube. In free-swimming individuals, lobes and mouth 

 may be absent and later reconstructed. Contractile vacu- 

 ole absent. 



The nucleus is round, oval or moniliform. The micro- 

 nuclei may be many and minute. Cross division results 

 in halves, of which one may remain and the other escape 

 fi'om tlie dwelling; the size differs much in different indi- 

 viduals. Complete life cycle, when known, may show 

 that some of the apparently specific forms are but stages 

 in life cycle of others. 



Species based so largely upon the forms of the secreted 

 dwellings may eventually prove to be but results of di- 

 verse secretional activities within one species. 



Conjugation unknown; reproduction by transverse fis- 

 sion follows nuclear condensation and dedifferentiation 

 of peristome; the posterior half grows a new mouth and 

 peristome and soon occupies the old dwelling, while the 

 anterior half swims free with no month and simpli^ spiral 

 meml)ranelle zone, secretes a new dwclliiiir. ■•uid (riftVrcnt i- 

 ates new mouth and peristomal apparatus. 



The old genus FoUiculina may be conv.-iiiciitly ,li\ i.h'd 

 into tentative subdivisions as suggested by Dons; hasrd 

 chiefly upon shape and proportion of the socrrti d casos. 



These groups mav be spoken of as gciit'i'a. iianirly, 

 FollicuVnuu SrHiifnJJIrMliua, F a va f nJV, nilm a and Psru<h>^ 



In Fn'liru^iru I.aniarrk. a^ r.-1i-\-l mI I.> Dm-,.. i1,.. ^ae 

 is commonly as uid.- a> Ion- Ww tuh^ ^liort and with- 

 out collar an. I \\wvv is uo >\nvA\ nor valv<'>. 



Tho onlv .prch.> an" thr ori-lnal /•'. a„n:"Vn „t Munlh^r 

 and tlu' }un,„yi, which wa. Ciard's r.lnUh, pn,iun, 

 and se.ms to h. an al.nonnality. Th. f n-^ii-water F. 

 boUoui svoiu> \o hr the .anir a^ /■'. nni/nilh^, and is re- 

 cord(>d from Kiiulan.l. Swil/.nlan.l and from France (as • 

 the A.srohius of llmno-ny). 



Til SriHlfnirirHliua tho sac i> lonuvr and the tube may 



