158 THE PHENOMENON OF 



duration. The primordial utricle seems to retract its 

 processes into itself, before it secretes the cellulose upon 

 its surface. Different, arid especially instructive in 

 reference to the relation of the cilia to the internal body 

 of the cell, is the behaviour in a series of Algoid plants, 

 in which the ciliary motion is of lengthened duration, 

 and which on this account have been hitherto included 

 among the Infusorial animalcules, namely, the Chlami- 

 domonada and the Volvocinese.* In Cklamidococcus 

 pluvialis, already mentioned above (p. 138), the active 

 cells, bearing cilia at the acute extremity, are born naked, 

 like the swarming cells of other Algae ; but within a few 

 hours the periphery of the body exhibits a delicate, 

 hyaline coat, which, by subsequent fluid secretion during 

 the about three-days-long duration of life and growth of 

 these "swarmers," becomes removed farther and farther 

 from the body of the cell, forming a separate membrane, as 

 it were, a loose coat around it. The ciliary motion persists 

 throughout this formation, only it gradually becomes 

 weaker and less active, since the cell-membrane becoming 

 gradually pushed up further from the base of the two 

 long cilia, more and more hampers their vibratile motion. 

 We have here, therefore, indubitable evidence that the 

 cilia belong to the proper body of the cell and the 

 primordial utricle bounding it, and not to the surrounding 

 cell-membrane.t Another Alga belonging to the same 

 group, which I have called Gfaococcus, produces, instead 

 of the more solid cell-membrane, a semifluid gelatinous 

 envelope, around its green body, which bears two very 

 long cilia at its acute extremity, and these become en- 



* Von Siebold (' de finibus inter regnum animale et vegetabile,' 1844, 

 p. 12) was the first who distinctly claimed the Volvocinese for the vegetable 

 kingdom. (See Williamson, 'Proc. Manchester Phil. Soc.,' vol. ix; 'Trans. 

 Mic. Soc. of London/ 1853; also Busk, 'Microscop, Trans.,' 1853. p. 31. 

 -A. H.) 



t Vide Von Flotow, 'Act. Acad. Nat. Cur.,' xx, p. 2, 1844, t. 25, f. 5870 ; 

 in reference to which figures, however, I must observe, that I have never 

 found the cilia retracted completely within the membrane. (Compare Cohn, 

 ' Nova. Act.,' xxii, and Abstract in this vol. ; also Schacht, ' Die Pflanzenzelle,' 

 p. 124. A. H.) 



