270 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



Additional material: D, 6861, (0), dredged in 19 m., Bahia 

 de San Lucas, Baja California del Sur, Mar. 11, 1949. 



Some observations on the development of the carposporophyte were 

 made in this species. The carpogonial branch systems and auxiliary cell 

 systems (the latter more numerous) occur just beneath the cortex and 

 arise by division and inward elaboration of the cortical filament cells to 

 produce a suspended, ampullar structure. In some of these systems a one- 

 celled branch at the base becomes enlarged and more deeply staining and 

 represents the auxiliary cell (fig. 20). In others a two-celled carpogonial 

 branch is produced in a similar position (fig. 19). The trichogyne reaches 

 the surface between the somewhat modified superficial cortical cells from 

 which the system is suspended. The actual fertilization process was not 

 observed, but soon after fertilization the auxiliary cell becomes enlarged 

 and more irregular in shape, and produces laterally and from below 

 numerous filaments of rather small, ovate cells which grow downward 

 and outward, while a subspherical gonimoblast mass is produced above. 

 At the same time the sterile, relatively vacuolate, larger cells immediately 

 surrounding the developing gonimoblast and just below the outer cortex 

 produce ramified filaments of elongate cells which grow downward and 

 around the gonimoblast to contribute to the sterile involucre. The fila- 

 ments which early grow out of the auxiliary cell from below seem ulti- 

 mately to be incorporated into the involucre. As the gonimoblast develops 

 into the subspherical carpospore mass the auxiliary cell becomes some- 

 what flattened and partially enveloped by the swelling carpospore mass, 

 so that in the mature gonimoblast it does not appear as a conspicuous 

 pedicel (fig. 21). 



Halymenia bifida is readily distinguished from other Mexican Haly- 

 menia species by its narrow, bifurcate blades. The subspherical carpo- 

 spore mass which partially envelops the inconspicuous old auxiliary cell 

 is also distinctive. 



Halymenia calif ornica Smith & Hollenberg 



PI. 13, fig. 57 



Smith and Hollenberg 1943, p. 216, figs. 18-19; Smith 1944, p. 243, 

 pi. 54, fig. 6, pi. 55, fig. 4. 



Thalli to 20 cm. tall, rosy red, plane, membranous, consisting of 

 several broadly falcate, short-stipitate blades from a small, pulvinate 

 holdfast; blades 3-7 cm. broad, 200-450 /x thick, the margins entire, 

 cuneate at the base to a compressed stipe 2-3 mm. long and 500-600 /* 

 in diameter; transection showing a thin, pigmented cortex and a broad 



