Dr. R. Caspary on the Hairs of marine Alga. 469 



sixteen cells, each tuft containing from five to fifteen hairs. 

 These hairs are nearly cylindrical, a little attenuated towards 

 the point, having in Chorda lomentaria the length of 0'5040"', 

 0-5070'", 0-5427'"; the single cells measuring, 0-0629'", 

 0-0500"', 0-0353"', 00425"'. Fig. 13 represents a hair of 

 Chorda lomentaria : those of Chorda filum and Pimctaria planta- 

 ginea are exactly similar. The undermost two or three cells con- 

 tain brownish grains ; the other cells in Punctaria plantaginea 

 contained only in the middle some grains, and those of Chorda 

 Jilum a roundish mass of slimy matter, a nucleus, attached to the 

 wall in the middle of the cells ; as the figure shows. 



In Leathesia tuberiformis, tufts of undivided long hairs are 

 found, slightly tapering to the point ; each tuft containing from 

 three to five hairs, and each hair from seventeen to eighteen cells. 

 Fig. 1 1 represents a hair of Leathesia tuberiformis. As I had 

 only an opportunity of examining young plants of |-^ inch in 

 diameter, I found the hairs not yet quite come to maturity. 

 Each hair proceeds from the uppermost cell of a little string of 

 cells, consisting of about three or four globular cells, having 

 brown grains attached to their walls. I found the undermost 

 cells of the hair to be the smallest and their walls scarcely re- 

 cognisable. They were entirely filled with colourless grains and 

 a colourless mucus. The upper three-quarters of the hair showed 

 clearly defined cells, each bearing in the middle attached to the 

 wall a nucleus of granular slime, from which threads ramify over 

 the whole wall, sometimes anastomosing. Fig. 16 represents a 

 cell with its nucleus and threads of slime. Iodine hardly colours 

 the walls of the cells of the hair, but the nucleus with its net- 

 work of slime is coloured dark brown and is brought very clearly 

 to light by iodine. The length of the whole hair was : 0-2950 ; 

 0-2320; and of the single cells in it : 0188; 00180; 0-0354; 

 0-305. 



The hairs of Sphacelaria scoparia are not like those of Spha- 

 celaria cirrhosa, single, or protruding laterally from the stem, 

 but are found in tufts of three to four in the axils of the spine- 

 like branchlets. To save space, I have not given a figure of a 

 whole branch, with its hairs in the axils of the branchlets. 

 The hairs are long, undivided, consisting of many cells. PI. XVI. 

 fig. 9 represents one. The undermost short cells are quite filled 

 with granular colourless matter; the upper, longer cells contain 

 this only in the middle as a little heap, but I had no opportu- 

 nity of ascertaining whether it is free or attached to the wall. 

 PI. XVI. fig. 12 represents the point of a branch of Sphace- 

 hria scoparia : a is the point of the main-branch ; 6 is the point of 

 a branchlet, and between the two in the axil at c are four young 

 hairs, consisting of only one cell, filled mth colourless granular 



