NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 289 



Fronds 10-14 cm. high, cylindrical, branching radially in all direc- 

 tions, diverging at 40-50°, deliquescent, without a main axis, 1100-1500 

 fi diam. ; apices short-attenuate, acute, with "fountain tip"; ultimate, 

 sharp, slender branches giving the dry plant a spiny appearance; cross sec- 

 tion showing a small core of longitudinal fibers within the medulla ; cysto- 

 carps unknown; tetrasporangia zonate, in the cortex immediately below 

 the surface ; tetrasporic portions of frond provided with abundant spinu- 

 lose projections. 



Type: D. 233, dredged in 4 meters at low tide, south shore of 

 Puerto Refugio, Jan. 28, 1940. Herb. AHF no. 36. 



D. 242, cast up at high tide, north shore beach, Puerto Refugio, Jan. 

 28, 1940; D. 254, dredged in 12-22 meters, Mejia channel, Puerto Re- 

 fugio, Jan.; D. 299, dredged in 60-80 meters over mud bottom, Gonzaga 

 Bay, Jan. 



This species is clearly distinct from any known member of the genus. 

 The character of the tetrasporic plants has confirmed its placement here. 



Genus SARCODIOTHEGA Kylin 



The three known species of this genus in our area are remarkable in 

 their external morphology, and are clearly distinct both from each other 

 and from other red algae. Their habit characters are so different from 

 other Gulf plants that they may readily be identified merely by glancing 

 at the several habit illustrations of the types. Anatomically the genus may 

 be recognized by its complanate structure, fibrous medullary core, zonate 

 tetrasporangia, and seriate carpospores. 



Sarcodiotheca linearis S. & G. 



Setch. & Card., 1937, p. 80, pi. 5, fig. 12a-b, pi. 15, fig. 35. 



The narrow, strict, infrequently branched fronds of this plant are 

 well illustrated and described by Setchell and Gardner. It is another sub- 

 littoral species known only from the extreme southern limits of our area. 

 The type specimen came from a depth of 40 meters in San Lucas Bay, H. 

 41, August (tetrasporic and cystocarpic). Recent collecting has yielded a 

 few more specimens, D. 627, dredged in 34-50 meters off Gorda Point, 

 February (sterile). 



Sarcodiotheca elongata (S. & G.) Setchell comb. nov. 



Anatheca elongata Setch. & Gard., 1924, p. 747, pi. 22, figs. 4, 5, pi. 64. 



In a marginal note in his personal copy of the 1924 publication, Setch- 

 ell has stated that this species is of the genus Sarcodiotheca. The investi- 



