NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 109 



Type: Holotype is Taylor 34-74c, Jan. 5, 1934, in box 3620 in 

 HAHF. 



Type locality: At a depth of 56 meters off Isla Clarion, Re- 

 villagigedo Archipelago, Mexico. 



Mexican distribution: Known only from the type collection 

 and from a second collection (Taylor 34-68) at the same locality but 

 from a depth of 103 meters. 



Cruoriella fissurata sp. nov. 

 Plate 7, fig. 6 ; Plate 24, fig. 1 



Thallo exigue calcificato, ad 10 cm. vel plus lato, laxius adhaerente, 

 recenti baud striato, siccato contracto radialiterque fisso, substratum 

 recludente inter partes angustas, anastomosantes thalli sicci, 200-600 /* 

 crasso; cellulis hypothalli 40-50 p. longis, 16-19 /t latis, 30-48 /t altis; 

 cellulis superioribus perithalli 12-13 [x latis. 



Thalli forming expanded, rose-colored, slightly calcified crusts to 

 10 cm. wide or more on rocks, shells, etc., rather loosely adherent to the 

 substrate, with few rhizoids, smooth and without marked striations when 

 fresh, when dry shrinking and splitting radially so as to expose the sub- 

 strate between the narrow, anastamosing parts of the dry thallus, the 

 margins wavy and more or less lobed, growing irregularly by small fan- 

 shaped areas, not normally becoming superimposed, when dry the sur- 

 face covered with minute, mound-like elevations which are in part 

 arranged so as to form minute, radiating, anastamosing ridges, but these 

 scarcely visible macroscopically, mostly over 200 /* thick, some well de- 

 veloped thalli 500-600 /x thick; hypothallus of very conspicuously con- 

 verging, diverging and anastomosing, fan-shaped groups of cell-rows, 

 the cells 40-50 fx long, 16-19 fx wide and 36-48 fi high, giving rise to 

 ascending, usually twice-forked cell-rows making up the perithallus, the 

 upper cells of these filaments more or less quadrate, 12-13 jx wide and 

 mostly shorter than broad; tetrasporangial and carposporangial nema- 

 thecia not seen; antheridial nemathecia (as seen in D. 3849a) small, 220 

 fx wide or more, slightly elevated, about 35 /* deep, the antheridia aris- 

 ing by transverse and longitudinal divisions of short, thick nemathecial 

 filaments, 2.0-2.5 ju. in diameter. 



Type: Holotype is Dawson 6830a in box 55445, including slide 

 1577, in HAHF. 



Type locality: Intertidal rocky shore, Cabeza Ballena, Baja 

 California, Mexico, March 11, 1949. 



