292 PERCY SLADEN TRUST EXPEDITION 
Dasyopsts, Zanardini. 
1. Dasyopsis STANLEYI, n. sp. (Plate 17. fig. 16.) 
Thallo elongato, subdichotomo, pauce ramoso, penicillis longis, gracilibus cincto; 
ramificatione radiata, constante e penicillis basim versus deciduis, spinas non 
relinquentibus. Stichidiis oblongis et cystocarpiis ex penicillis orientibus. An- 
theridiis non visis. Thallo alto 16cm. MHabitu Dasye elegantis. 
Cargados Carajos, 30 fms.; in alcohol and dry specimens. 
To rightly understand the new species of Dasyopsis, it may be worth while to give 
a short account of the characters of the genus. Dasyopsis has a sympodial mode of 
growth; the stem or axis being composed of short branches with definite growth ; 
these are pushed aside by their own first branch, and the distance between the base of 
the mother-branch and the point of insertion of its first branch varies in different 
species. 
But this is a feature Dasyopsis has in common with all Dasyeze; its special character 
consists in the absence of true pericentral cells. The cells that surround the central 
tube are not originally segments of this tube, as in the other Rhodomelacee, but they 
are downward-growing hyphe, the mother-cell of which is cut off from the branch that 
is pushed aside when sympodial growth sets in (Pl. 18. fig. 32, m). The hyphze may be 
of the same diameter as the central cells, in which case they resemble true pericentral 
cells, but they have quite a different origin. The displaced branches continue to 
develop, they are shorter or longer, naked or corticated, according to the species, and 
carry several monosiphonous filaments, the so-called penicillus, at the apex. 
Dasyopsis Stanleyi consists of a subdichotomously divided principal axis or stem, 
carrying at indefinite intervals branches of unlimited growth, which may ramify again 
and are surrounded at the top by monosiphonous penicilli. This pretty alga so much 
resembles Dasya elegans that I felt at first inclined to take it for that species; after 
careful examination, however, I discovered that the plant has the characteristic 
structure of Dasyopsis; the branches of definite growth are separated by only one 
short segment from each other, and grow out in any direction from the main axis. As 
every branch or so-called penicillus gives off a downward-growing hypha, the central 
axis soon increases in thickness ; true pericentral cells are of course absent. 
The penicilli are composed of cells having a breadth of 6-13 ,; their length varies 
from being almost square at the base to 72 at the top. They are very delicate and 
soon fall off, unless they happen to bear cystocarps or stichidia at their base. ‘The 
stichidia were very rare in my preparations; I observed only one but unfortunately 
lost it; I saw, however, that it was long and cuspidate. The cystocarps were numerous 
in fertile specimens. 
2. DASYOPSIS APERTA, n. sp. (Plate 17. fig. 17; Plate 18. fig. 32.) 
Thallo ex axibus principalibus primo surgentibus, postea decumbentibus constante, ende 
denuo rami adscendentes nascuntur. Apice axis principalis et ramorum penicillis 
ramulosis, monosiphoniis cincto, penicillorum pilis postea decidentibus, basi 
