BOT.-VOL. II.] HUS—PORPHYRA. 229 



appearance of a young frond of P. nereocystis, being linear 

 to slightly lanceolate in the more developed fronds. The 

 margins are slightly crenulate and more or less irregular, 

 but the frond is not lobed or even laciniate. The base is 

 cuneate to slightly orbicular, exhibiting a slight aureole 

 around the point of attachment. Attachment is by means 

 of a disc. 



The distromatic nature of the frond readily distinguishes 

 the plant from P. nereocystis. The cells are square or from 

 once and a-half to twice as broad as high. The surface 

 jelly is thick (PI. XXI, figs. 15a and 15^). 



The specimens examined show only antheridia, and from 

 this it is supposed that the plant is dioecious. The anther- 

 idia are found towards the tip of the frond and along the 

 edges. They evidently spread gradually over the whole 

 frond. 



The antheridia form the chief characteristic of the 

 species. The antherozoids are arranged in groups such as 

 are found in no other species, and exhibit a marked regularity 

 in the division. As in all species of Porphyra, the anther- 

 idium-mother-cell, to produce the antheridia, undergoes a 

 cruciate division perpendicular to the surface of the frond. 

 The first reproductive division (in the antheridium) is par- 

 allel to the surface of the frond. This is followed by a 

 cruciate division perpendicular to the surface of the frond, 

 after which another parallel and another cruciate division 

 take place, thus giving rise to sixty-four antherozoids in 

 four tiers of sixteen each (PL XXI, figs. 16, 17a, i']b. PI. 

 XXII, fig. 27). 



When the antheridia are fully ripe, the jelly-walls between 

 the antherozoids dissolve before the surface jelly goes into 

 dissolution, so that the antherozoids are arranged more or 

 less irregularly in rectangular groups. 



Habitat. — On rocks. Zone? 



Distribution. — As yet reported from but a single locality 

 on the Pacific Coast (36° 45' N. lat.). 



Locality. — Carmel Bay, Monterey County, California 

 (Mrs. J. M. Weeks!). 



