Dr. R. Caspary on the Hairs of marine Algce. 467 



II. Haii's composed of many cells : 



1. Undivided: 



A. Single ones : Sphacelaria cirrhosa. 



B. Placed in tufts of 5-16 : Chorda filum and lomentaria ; 

 Punctaria plantaffinea ; of 4-5 : Leathesia tuberiformis ; 

 in the axils of the branchlets : Cladostephus spongiosus, 

 Sphacelaria scoparia; in an undefined number at the 

 couceptacles : Cystoseira granulata. 



2. Divided, dichotomously : Rhodumela subfusca ; Polysipho- 

 nia urceolata, fibrosa, nigrescens; in the couceptacles amongst 

 the antheridia : Cystoseira granulata. 



We turn now to the description of the hairs in each plant. 



The hairs in Callithamnium Daviesii are very long, cylindrical, 

 consisting of one cell, rounded at the apex, without a nucleus or 

 granular contents, but towards the apex (PI. XVI. fig. 10) there is 

 in younger hairs a small portion of a slimy, not granular matter, 

 filling out the whole breadth of the hair. The hair is produced 

 here and there at the apex of the cells of the stem (see tig. 10, 

 which represents a branch of Callithamnium Daviesii with two 

 hairs). Their length is : 0-1094; 0-0474; 0-0712 of a French 

 duodecimal line. I did not find any hairs on other species of 

 Callithamnium, i. e. on Call. Ruthii /3. purpureum, polycarpum, 

 Twneri, and two other species. Therefore, and as the nucleus 

 in Call. Daviesii is a free one in the apex of the cells, whilst the 

 other Callithamnia just named have the nuclevis attached to 

 the middle of the wall of the cell, I doubt whether this species 

 rightly holds its place in the genus Callithamnium. It would 

 be desirable to make it a point for observation, whether Call. 

 Daviesii has favelloe and tetraspores : I myself have seen neither, 

 but in March and April of this year plenty of simple globular 

 spores. 



Hairs, which are almost entirely like those of Callithamnium 

 Daviesii, but standing in whorls round the stem, where two 

 cells join, occur in six species of Ceramium enumerated above, 

 which I have examined in a living state. But probably all the 

 species of the genus will exhibit such hairs, if searched for. 

 They are cylindrical, with a rounded apex, without granular 

 contents or nucleus, but showing in a young state here and 

 there heaps of a not granular slime, which in the adult hair is 

 only found at the apex in a small quantity. Ceramium rubrum, 

 when it is uninjured, exhibits these hairs particularly numerous 

 on the apices of the branches ; some branches are so covered 

 with them, that they look like brushes. Cer. flabelligerum, acan- 

 thonotum and ciliatum have such hairs besides the spines, but 



31* 



