262 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 3 



confined largely to the prostrate parts ; apices acute, not attenuated ; cor- 

 tex and subcortex of about 3 layers of more or less isodiametrical cells 

 surrounding a large medulla of elongated cells, the two areas not very 

 distinct in cross sections; tetraspores produced abundantly in cortical 

 cavities of slightly swollen short branchlets or tips of branches. 



Type: (tetrasporic) D. 651, on middle littoral rocks, rocky point 3 

 mi. north of Kino, July 16, 1940. Herb. AHF no. 18. 



D. 288, rocky shore, Puerto Refugio, Jan. 



Gelidiella mexicana sp. nov. 



Plate 43, Fig, 3 



Frondes 4-6 mm. altae, floccosae; ramis cylindricis, 120-180 n diam. ; filis 

 erectis copiosis, e partibus brevibus, prostratis, rhizoideo-affixis; apicibus acutis; 

 tetrasporangiis nondum visis. 



Plants 4-6 mm. high, forming small, dense tufts, cylindrical through- 

 out, 120-180 fi in diam.; erect parts rising abundantly from short, pros- 

 trate parts firmly attached to the substratum by abundant short rhizoids, 

 frequently and irregularly polystichously branched above the prostrate 

 parts ; apices acute, not attenuated ; cortex and subcortex of about 3 layers 

 of cells, not very distinct in cross section from the large medulla; tetra- 

 spores unknown. 



Type : D. 401a, on middle littoral rocks with other small algae. Pond 

 Island, Feb. Herb. AHF no. 19. 



D. 328a, shore of Gonzaga Bay, Jan. (somewhat larger throughout, 

 150-200 /x diam.). 



D. & R. 3227, from tide pools, Cabo Arco near Guaymas, December, 

 may be distinct yet closely related here, but the specimens are not suffi- 

 ciently mature to merit description. It is similar in size and apparently 

 in branching but is not so closely tufted, has arching stolons of smaller 

 diameter than the rest of the parts and attachment organs only at points 

 opposite the erect branches, these points being spanned by short, arching 

 stolons. More material of this form is needed to establish its identity. 



Gelidiella ? refugiensis sp. nov. 

 Plate 43, Figs. 4-6 



Frondes 1-1.5 cm. altae, ramis erectis divaricatisque, 150-300 M- diam., sub- 

 cylindricis usque ad compressis compositae ; ramificatione vulgo disticha, laxa, ir- 

 regulari ; partibus prostratis exiguis, per uncos disciformes parvos irregulares af- 

 fixis; apicibus acutis; sporis subsphericis indivisis (monosporis) in subcorticibus 

 caverno excavatis ramorum, brevium, terminaliura positis, 20-50 pi diam.; per 

 foramina subcorticis emittentibus. 



