16 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 26 



Type locality: On old Laminaria, Friday Harbor Docks, San 

 Juan Island, Washington. 



Mexican distribution: Pacific Baja Calif. — D. 13234a, Islas 

 Todos Santos, 40 m. ; D. 20267 (Neushul), Sacramento Reef, 15-17 

 m.; D. 20396 (Neushul) Isla Asuncion, 6-13 m.; D. 20353a (Neushul) 

 Bahia San Hipolito, 8 m. 



The Mexican specimens, although in agreement in general char- 

 acters with this species are much smaller throughout than the type 

 and have the main axial cells less elongated (1.5-2 diam. instead of 

 3-5 diam.). The apparent absence of gland cells seems enigmatic, but 

 Dawson (1954) has pointed out that in some southern California 

 collections gland cells may be abundant or sparse. Nevertheless, the lack 

 of gland cells in the present materials calls for further study of additional 

 collections of this plant and a comparison of the range of variability 

 in this and other characters in conjunction with studies of the Japanese 

 A. miharai Tokida, which is apparently exceedingly like, if not identical 

 with A. glanduliferum. It was differentiated by Tokida on the basis 

 of "paucity of gland cells" and the tetrahedral division of the sporangia. 

 Smith (1944) has pointed out, however, that the tetrasporangia of A. 

 glanduliferum are cruciate "but often appearing as if tetrahedrally 

 divided." It seems probable that the Japanese and more northern 

 Pacific coast plants are conspecific, but if it should be shown that the 

 small, short-celled plant of southern California and Baja California, with 

 sparse or absent gland cells, is actually distinct from the larger, northern 

 examples, the application of the name A. scrippsiana Dawson will have 

 to be considered once again. 



Antithamnion hubbsii sp. nov. 

 PL 5, fig. 2; PI. 6, fig. 3 



Thalli epiphytici, plus minusve prostrati, axe primario per rhizoideum 

 (interdum e fere omni cellula partis prostratae enascens) crebro affixo; 

 rhizoideum multicellulare, uniseriatum c. 30-40 /x diam., in discum multi- 

 cellularem desinens; axes primarii 50-60 fi diam., cellulis 4-5 plo longioribus 

 quam latae, ramificatione sparsa indeterminata, omni cellula, autem, prope 

 extremitatem distalem, par ramorum determinatorum patentium aut quasi 

 ascendentium habente; rami primarii determinati c. 1 mm. long. 30 fi diam. 

 prope basim, ecellula basali subspherica enascentes, parte in basali ramulis 

 oppositis pinnatis necnon parte in distali ramulis abaxiale secundis praediti, 

 ramulis secondariis simplicibus aut ramellos nonnullos abaxiales habentibus; 

 omnis ramulus attenuatus, admodum acutus, e cellulis 2.0-2.5 plo longioribus 

 quam latae compositus; rami secondarii indeterminati axis primarii e cellulis 

 basalibus subsphericis ramorum lateralium primarium determinatorum ena- 

 scentes; rhizoidea affixionis e hac cellula basali quoque plerumque enascentia; 

 glandicellulae sparsae, in ramis secondariis ramorum lateralium determinator- 

 um plerumque enascentes, in cellulis duabus sitae; reproductio ignota. 



Thalli epiphytic, more or less prostrate, the primary axis attached 



