470 Dr. R. Caspary on the Hairs of marine Algce. 



matter^ and not yet separated by a partition-wall from the mothef^^' 

 cell. This and the walls of the cells of the hair however sooii 

 make their appearance, and from the internal heap of grains, as 

 a centre, the cells grow in length at both ends. 



In Cladostephus spongiosus, also in the axils between th^ 

 branches and their branchlets, are found tufts of three or four 

 hairs, which are undivided, slightly tapering to a blunt point, 

 containing from eleven to fourteen cells. The development of 

 these hairs is very interesting. Fig. 7 represents a branch with 

 four mature hairs in the axil between the main-branch and its 

 branchlet. The undermost cells contain granular substance, 

 slightly tinged with grayish brown. The uppermost contain 

 granular, colourless substance only in the middle and attached 

 to the wall. If touched with iodine, the heap of granules attached 

 to the wall loses almost entirely its granular appearance, and 

 looks like a solid dark brown coloured mass of slime and iodine ; 

 a network of little threads of slime, coloured brown, proceeding 

 from the slimy nucleus, makes its appearance, which is invisible 

 before the application of iodine. Fig. 8 represents one cell with 

 this network of slime-threads. The young hairs appear first as 

 protuberances in the axil between the branch and branchlet. 

 Fig. 14 shows a point of a branch of Cladostephus spongiosus : 

 b is the main-branch, a the branchlet, and between both are two 

 hairs, as yet protuberances, filled with brownish grains and not 

 yet separated by a partition-wall from the cell from which they 

 proceed. Fig. 15 shows also the point of a branch, which exhibits 

 in its axil four hairs in a more developed state. They are already 

 separated from the mother-cell by a partition-wall, and the walls 

 of their own cells are about to make their appearance, beginning 

 from the point, as the one hair at the right-hand side shows 

 already at its point such a division-wall. The young cells in 

 the hair are quite filled with granular substance, but this soon 

 separates from the division-walls, and the cell growing from the 

 heap of granules in both directions in length, bears it finally 

 only in the middle, whilst it sends out along the walls of the 

 cell the threads of slime above mentioned. 



Cystoseira granulata has at the aperture of the conceptacles a 

 thick tuft of undivided hairs, which partly consist of colourless, 

 empty cells, being from 00648-0'0768'" long, partly of very 

 small cells, the walls of which are covered with brown grains. 

 The latter sort of hairs is found more in the interior of the 

 aperture, the first sort near its mouth. Fig. 23 represents a 

 point of one hair of the interior part of the aperture, showing 

 cells, the length of which is only l|-2 times as large as their 

 breadth, and bearing brown grains on their walls. The cells of 

 such a hair measured in length : 00113"^ 0-0266'"; 0-0202'"; 



