NOTES ON THE DEVELOPMENT OF THE HOLDFASTS 
OF CERTAIN FLORIDE#:, 
Git wie M. DERICK, 
(WITH PLATES -XXI—XXIII AND FIVE TEXT-FIGURES) 
Wir the exception of passing references in various works, 
two articles, the one by Borge (1), the other by Strémfelt (8), 
include, I believe, all that has been written upon the holdfasts of 
the alg. The former deals with a few members of the Chlore- 
phycee ; the latter is very comprehensive, but it is without illus- 
trations and gives no specific details. Therefore, the study of 
the development of the holdfasts of some nearly related species 
of the Rhodophycez has seemed advisable. 
The observations described in this paper were made at the 
Marine Biological Laboratory, Woods Hole, Mass., during the 
summers of 1896 and 1897, and the work was finished in the 
Botanical Laboratory of McGill College. | 
Cultures of the spores of several species were made ae | 
various conditions. Ordinary glass object-slides were git 3 : 
flat porcelain dishes, either white or painted black. The vesse j 
were filled with filtered sea-water and in them were laid 2 7 
bearing ripe spores. The spores usually sowed i 
twenty-four hours, in which case the plants were removed. . 
of the dishes were fed by a gentle stream of running es 
others were disturbed only three times a day, when ppd 
was drawn off by a siphon and replaced by filtered se . 
The latter method proved much the better of the two. ier 
The color of the background had no effect upon the Cultures 
ment of the spores, nor were the plantlets heliotropic- se 
kept in a shaded place flourished best, even 4 short ao 0 
direct sunlight killing plantlets. It is to be pases je 
record of variations in the temperature and the dens! fs 
water was kept. Oltmanns (6) has conclusively show? 
of the 
t such 
[ocros 
246 
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