446 
PACIFIC SCIENCE, VoL VIII, October, 1954 
Centroceras clavulatum (Ag.) Montagne, 
in Durieu 1846: 140. Ceramium clavulatum 
C. Agardh, in Kunth 1822: 2 (Peru) 
Fig. 54Z> 
LOCAL DISTRIBUTION: Common in various 
situations, epiphytic or saxicolous. Most fre- 
quently found as a component of low algal 
turfs on rocks. The example figured is a rather 
lax form from drift, Sta. 3 (11101). 
Key to the Species of Ceramium 
1. Cortication continuous except in young 
parts, the cells arranged in longitudinal 
rows C. huysmansii 
Cortication + — discontinuous, banded, 
except sometimes in old parts, the cells 
not in longitudinal rows 2 
2. Cortical bands provided with verticils of 
bulbous hairs C. fimbriatum 
Cortical bands without bulbous hairs . . 3 
3. Tetrasporangia radially arranged 4 
Terra sporangia unilaterally arranged .... 6 
4. Cortical bands divided by a transverse line; 
tetrasporangial nodes + — catenate .... 
C. taylorii 
Cortical bands not divided by a transverse 
line; tetrasporangia not causing much 
catenate development of nodes 5 
5. Internodes long; filaments very slender, 
partly repent C. procumbens, prox. 
Internodes very short; filaments rather 
coarse, erect C. maryae 
6. Tetrasporangia free, not involucrate 
C. clarionense 
Tetrasporangia immersed, involucrate. .7 
7. Cortical band of small, angular cells 
throughout C. mazatlanense 
Cortical band divided, the lower third of 
transversely elongated cells 
C. gracillimum var. byssoideum 
Ceramium fimbriatum Setchell and Gardner 
1924: 777, pi. 26, figs. 43, 44 (Gulf of 
California) 
Fig. 55^ 
LOCAL DISTRIBUTION: Growing as a minute 
epiphyte on Halophila, Sta. 4 (11173). 
Ceramium taylorii Dawson 1950^: 127, pi. 
2, fig. 13, pi. 4, figs. 31-33 (Baja California, 
Eg. 55i, . 
LOCAL DISTRIBUTION: Epiphytic and saxi- 
colous, forming dense tufts 1.0-1. 5 cm. high, 
Sta. 8 (11256, 11258). 
The obscure Ceramium loureiri Agardh 
(1824: 137) from marine rocks of Cochin 
China is possibly referable here, but it is 
impossible to recognize it from the meager 
description. 
Ceramium huysmansii Weber van Bosse 
1923: 322, fig. 115a, b (Indonesia). Cera- 
miella huysmansii (W. v B.) Bprgesen 1953: 
47, figs. 18, 19 
Fig. 55^ 
LOCAL distribution: Creeping on dead 
coral fragments, Sta. 7 (11245). 
The present material is somewhat more 
slender and more branched than that de- 
scribed and illustrated by Weber van Bosse, 
but has the characteristic cortication, habit, 
and simple tips of her species. The tetraspor- 
angia are embedded beneath the cortex, and 
in the development of these the thallus be- 
comes constricted in a somewhat catenate 
manner. 
Bprgesen has recently proposed the new 
genus Ceramiella for this species and suggested 
that other species such as C. maryae may 
belong in it. He quotes, however, from a 
letter by Mme. Genevieve Feldmann who 
considers the plant a species of Centroceras. 
I prefer here to retain both C. huysmansii and 
C. maryae in Ceramium pending further study 
of this problem. 
