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



Harvey calls tlie hairs of Seaweeds either by this name, see 

 ' Manual/ 1849, p. 31, or "fibres," I. c. p. 71, or "filaments," 

 I. c. p. ]2. We would propose that the term "filament" be 

 banished altogether from algology, as having already in phse- 

 nogamous botany a fixed signification ; particularly as it is used 

 in algology not only in one signification, but, what is scarcely 

 credible, va. four ; signifying, as mentioned, first, "hair,^' I.e. 

 p. 12 ; secondly, " stem,'^ as in the Confervse, I.e. p. 198, which 

 Kiitzing with a very good name calls " trichoma ^^; thirdly, 

 " strings of cells placed end to end," forming in the stem only 

 a component part and not being isolated as such, /. c. p. 146 ; 

 fourthly, "elongated single cells," as in Codium tomentosum, 

 ' Phycol. Brit/ t. 93, ' Manual,' p. 193. What good can be ex- 

 pected from such an indefinite signification of a term, particularly 

 in science, where clearness of expression is the first condition ? 

 The expression "fibre," which is also used for signifying the 

 hairs of Seaweeds, is equally to be rejected. A "fibre" is in 

 other parts of botany an elongated cylindrical or flattened body 

 of no cellular texture, but simply consisting of solid cellulose, 

 as the spiral fibre, &c. In analogy with this signification, I 

 propose to restrict the term in algology for such thin, elongated, 

 solid, more or less cylindrical bodies, not having cellular texture, 

 as are e. g. found in the genus Schizosiphon, Kiitz. (see ' Sp. 

 Alg." p. 327, *Phyc. Gen.' p. 233), where the sheaths split into 

 such long, thin, often curled and spirally twisted bodies, probably 

 composed of gelatine. The term " hair," finally, is in other parts 

 of botany applied to " cells of soft thin walls, attached to the 

 external surface of the plant, of different form or arrangement " 

 (see Schleiden's ' Wissenschaftliche Botanik,' i, p, 258) ; and this 

 signification of the term " hair" is entirely that which we attribute 

 to the word in algology, although with this addition, that such 

 bodies bear no fruit or antheridia, nor are threads of fixation. 



After having thus fixed the signification of " hair," we shall give 

 a general survey of the sorts of hairs we have examined, and then 

 describe their form and development in the individual plants. 



The following table shows the kinds of hairs we have found. 

 I. Hairs of one cell : 



1 . Single ones : Callithamnium Daviesii. [We quote the names 

 according to Harvey's ' Manual,' and omit for the sake of 

 brevity the name of the author.] 



2. Many placed in an irregular whorl at the junctions of two 

 cells of the stem : Ceramium ruhrum, strictum, nodosum, 

 flabelligerum, acanthonotum, ciliatum. 



