NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 93 



parts of a single axial filament each cell of which bears four quadrately 

 disposed, branched filaments whose end-cells form a fairly compact 

 cortical tissue, in older parts with numerous rhizoidal filaments sur- 

 rounding the central axial filament; sexual thalli dioecious; cystocarps 

 numerous, small, globose, deeply embedded in the thallus; antheridia 

 and tetrasporangia not seen. 



Type : Holotype not designated. Syntype collections by Dr. Ander- 

 son and by Miss Lennebacker are probably in the Farlow Herbarium, 

 Harvard University, Cambridge, Massachusetts. 



Type locality: Not specifically designated. Syntypes came from 

 Santa Cruz and from Santa Barbara, California. 



Mexican distribution : Pacific Baja Calif. — D. 8877, intertidal, 

 on sandstone at end of headland, Punta Baja, Jan. 



The Mexican material is small, not exceeding 4 cm. in height, but is 

 abundantly provided with mature and developing cystocarps. A cursory 

 examination of the gonimoblast development indicated some apparent 

 differences from that reported in Gloiosiphonia capillaris (Huds.) Carm., 

 but a critical study cannot be presented here. 



The discovery of this species at Punta Baja extends the known range 

 of this species southward by six degrees of latitude, from Carmel, Cali- 

 fornia. 



Endocladiaceae 



Key to the Mexican Genera and Species 



1. Thalli dichotomously branched; segments smooth 



Gloiopeltis minuia 



1. Thalli polystichously branched; segments beset with many 

 minute, spine-like branchlets . . . Endocladia muricata 



Gloiopeltis minuta Kylin 



Plate 7, figs. 8-9 



Kylin, 1941, p. 7, pi. 2, fig. 4 (invalidly described for want of Latin 

 diagnosis) ; Dawson, 1951, p. 52. 



Thalli saxicolous, lubricous, forming extensive colonies, 0.7-1.0 cm. 

 high, consisting of a spreading disc from which numerous cylindrical, 

 2-6-times irregularly dichotomously branched, erect fronds arise; erect 

 parts 200-250 /^ in diameter below, 400-600 fx above, the terminal seg- 

 ments abruptly attenuated and acute ; transection of sterile parts showing 

 a radial structure of dichotomously branched filaments of thick-walled 



