REJUVENESCENCE IN NATURE. 143 



larger spores, on the contrary, exhibit a strong mem- 

 brane and dark olive-brown contents. After they are 

 sown the membrane swells up, and the contents become 

 divided, at least in some genera of the Fucoidese, into 

 two, four, or eight parts, which pass at once into germi- 

 nation, a process which reminds us of the above-described 

 behaviour of the spores of the Closteria and certain 

 Zygnemacese. As a last example of the occurrence of 

 double fructification in the group of Algae, I mention 

 Chantransia. The ordinary, long-known fructification of 

 this genus consists of globular, very thin coated germ- 

 cells, having a central rose-coloured vesicle in the light 

 verdigris green contents, which germ-cells are formed 

 separately in the terminal cells of the tufted lateral 

 branchlets, and are set free by the rupture of the parent- 

 cells. They have no independent motion, but probably 

 germinate directly after they are discharged; on this 

 point, however, we have no certain observations. In 

 the same plant, and indeed on the same "stocks" and 

 branches, there occurs more rarely a second kind of 

 fructification,* in which the cells forming the links of 

 the branches swell strongly at the side, and form a large 

 thick-coated spore in the protruberance, which becomes 

 shut off as a distinct cell. 



Chantransia therefore exhibits two kinds of motionless 

 reproductive cells, the smaller of which are probably 

 immediately-germinating gonidia, the larger resting 



The decision of their true import therefore requires, on the one hand, fur- 

 ther observations completing the history of their formation and life ; and, on 

 the other, the discussion of the question, whether the formation of actiw, 

 and, as we have seen, in many cases sterile gonidia, is not to be regarded 

 as a precursor of the formation of spermatozoids, just as in a higher group, 

 the formation of two kinds of spores, the former of which are likewise, in 

 many cases, sterile, must be regarded as an anticipation of the contrast of pollen 

 and embryo-sac. (See Thuret, ' Comptes Rendus,' April 25, 1853 ; Transl. 

 in ' Annals of Nat. History/ 2d ser., vol. xii, p. 64, who shows that the 

 autherozoids do fecundate the spores of Fucoidese. A. H.) 



* I observed this in October of last year in a form of Chantransia chalybea, 

 Fries, very frequent at Freiburg, which Kiitzing (' Sp. Alg.,' 430) mentions 

 as Ch. chalybea, var. radians. 



