REJUVENESCENCE IN NATURE. 181 



tears at both ends, and the two stick-shaped young ones 

 strip it off, slipping out from the two opposite sides of 

 the old coat, like a finger from a glove. I have observed 

 a similar skinning in Euastrum (Cosmariuni) margariti- 

 ferum* In Closterium (Penium} curtum^ on the other 

 hand, I saw the mother-cell membrane tear cross ways, in 

 the middle, during the division, so that its two halves 

 separated and were stripped off by the two new indi- 

 viduals on opposite sides. I have observed a very pecu- 

 liar mode of the phenomenon of skinning in a new germs 

 of Palmellacese, which I have called Schizochlamys.\ The 

 globular cells of this little Alga produce a hyaline cell- 

 membrane, which becomes removed to some distance 

 from the green body of the cell by subsequent secretion 

 of fluidish jelly; soon, however, (probably from endosmose,) 

 becoming unable to withstand the expansion of the jelly, 

 it splits in the direction of an equatorial circle, by a clean 

 line, into two similar halves, or, if the dehiscence takes 

 place by two circular lines cutting at right angles, into 

 four similar pieces. This splitting and peeling of the 

 membrane, either coincides with a division of the internal 

 cell-mass, or it occurs without any such division. By 

 frequent repetition of this process the cell gradually 

 becomes surrounded by an accumulation of old fragments 

 of the membranous shell, which are held together by the 

 extremely transparent jelly set free. The division of the 

 cell may be either a simple halving, in which case each 

 part is immediately clothed again with a hyaline cell- 

 membrane, or double, through the cells produced by the 

 first division separating immediately into two cells, without 

 previously acquiring a coat of cell-membrane, and therefore 



Closterium Trabecula belongs to the genus Docidium; according to Nageli, 

 to the genus Pleuroteenium. Focke, moreover, confounds at least two 

 distinct species of this geuus under his Closterium Trabecula. 



* Eocke, 1. c., t. ii, lig 17, represented in division, but without notice of 

 the skinning. 



t Ralfs, ' Brit. Desmidiese,' t. xxxii, f. 9. 



\ Kiitzing, 'Sp. Alg.,' p. 891. Perhaps Hassali's Sorospora Ei 

 (Hass., t. Ixxviii, f. 8, a,) may belong to my Schizochlaniys gelatinosa. 



