2o6 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



The patches of sporocarps are easily distinguished from 

 the patches of antheridia. The former are of a uniform, 

 dark violet color, which gradually, towards the center of 

 the frond, fades into the gray- or brown-violet of the vege- 

 tative part of the frond. The patches of antheridia, on the 

 other hand, are nearly colorless when fully ripe. They are 

 usually very narrowly triangular and radiate from the center 

 of the frond. These patches contain the unripe antheridia 

 and are, towards the center of the frond, of a light violet 

 color, lighter than that of the surrounding sporocarps, but 

 deeper violet than that of the vegetative cells. 



S^orocar-ps. — The first division of the sporocarp is cru- 

 ciate and perpendicular to the surface of the frond. This 

 is followed by a division parallel to the surface of the frond, 

 thus giving rise to eight segments in two tiers of four each, 

 every one of which undergoes a cruciate division, thus giving 

 rise to thirty-two spores in two tiers of sixteen each (PL 

 XX, figs. 5a and 5<^; PL XXII, fig. 25). Rarely there is 

 an additional parallel division in some or all the segments 

 formed by the last cruciate division. 



Antheridia. — The antheridium-mother-cell undergoes a 

 cruciate division perpendicular to the surface of the frond, 

 giving rise to four antheridia. The first reproductive divi- 

 sion of the antheridium is parallel to the surface of the 

 frond. This is followed by a cruciate division, after which 

 another parallel division takes place; so that each anther- 

 idium now contains sixteen segments arranged in four tiers 

 of four each. Each of these segments now undergoes first 

 a cruciate division and then a parallel division; so that each 

 antheridium now contains 128 antherozoids, arranged in 

 eight tiers of sixteen antherozoids each (PL XX, fig. 6; PL 

 XXII, fig. 28). In this species the last division is nearly 

 always regular and fully carried out. 



Sometimes the vegetative division of the antheridium- 

 mother-cell does not take place; so that four times the 

 number of antherozoids are formed in an antheridium. 



Economic Use. — Porfhyra perforata is one of the edible 

 seaweeds, and is largely collected for food by Indians and 

 Chinese on the Pacific Coast. 



