EEO | 
plant a peculiar appearance reminding one of the Antithamnia. The main axis is 
distinct, increasing gradually in thickness downwards. A little above the base it is 
over 100 x thick and consists there of cells about twice as long as broad, while 
the cells in the upper part of the plant are 3—4 times as long as broad. The lower- 
most two or three joints of the stem are provided with cortical filaments which 
Fig. 274. 
Callithamnion sp. A 80:1. B 150:1. 
continue their way into the basal disc. All the cells contain one nucleus and nume- 
rous elongated chromatophores. The upper end of the branches are 12 « thick; 
they are rounded, never terminating in a hair or in a point. The plant bears a few 
sporangia situated in the place of a pinnula. They are tetrahedrically divided, 60 w 
long, 46 x broad. 
A pectinate ramification like that described above seems to be rare within the 
genus Callithamnion. According to J. AGARDH it occurs in C. scopulorum Ag. the pinne 
of which are “rarius interiore latere pinellis brevissimis secundis quarum inferiores 
