126 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 26 



PLATE 10 



Fig. 1-3. Callithamnion marshallense Daws. Fig. 1, Branching habit X 70, 

 Fig. 2, A tetrasporangial branch. X 162; Fig. 3, A catenate holdfast, 

 X 60. 



Fig. 4-5. Callithamnion rigidum sp. nov., from the type collection. Fig. 4, 

 Branching habit, X 60; Fig. 5, A tetrasporangial branch, X 128. 



Fig. 6-7. Callithamnion ramosissima Gard., from D. 8566. Fig. 6, A tetraspor- 

 angial branch, X 100; Fig. 7, Apex of a growing plant, X 210. 



