from the Calif ornian Coast. 251 



shaped, more like those of the last species, but not toothed. 

 The lip is distinct. 



I h *ve received only a minute portion, without vesicles. 



Ba of San Francisco. 



3. Sertularia corniculata, Murr. PI. XI. fig. 3. 



Cells not quite opposite, sometimes nearly alternate, forming 

 an open cup resting on the stem; lip not distinct; exterior 

 margin somewhat projecting at tip ; a single one in the axilla of 

 each pinna. Vesicles pear-shaped, with two long points pro- 

 jecting like horns at the thick end ; aperture between them. 



This is a very elegant little species, and is easily distinguished 

 by the two long horns at the top of the vesicles, which remind 

 one somewhat of a fool's-cap, and by the wholly open cells. 



Bay of San Francisco. 



4. Plumularia gracilis, Murr. PI. XII. fig. 1. 



Stem slightly flexuose, branched ; branches alternately pin- 

 nated ; cells ranked closely in twos and threes ; tubulous, with 

 a plain rim slightly peaked in front ; vesicles oblong-oval. 



The characters of this Plumularia do not differ greatly from 

 those of P. falcata -, but its habit is so different that it can 

 scarcely be mistaken for it. The branches are closer, and more 

 thickly set, than in P. falcata ; their arched disposition is want- 

 ing ; and the whole plant has more the aspect of a Sertularia 

 than a Plumularia. The cells are proportionally larger than in 

 P. falcata ; instead of a plain truncate rim, it has one slightly 

 peaked in front, or excised at the sides. Each cell has also a 

 sort of support, like a triangular buttress, below it, marked or 

 lined off from the cell itself. 



Bay of San Francisco. 



5. Plumularia struthionides, Murr. PI. XII. fig. 2. 



Shoots simple, plumous, the pinnae alternate; cells close, 

 each occupying the whole of one side of the joint to which it is 

 attached, cup-shaped, with a toothed margin, of which the teeth 

 are unequal, the one in front projecting much more than the 

 rest ; vesicles gibbous, girt with toothed ribs. 



This species is nearly allied to P. crisiata, but is much closer 

 in habit, both the pinnae and the cells being nearer each other. 

 The cells are wider-mouthed and shallower. Besides the pro- 

 jecting process in front, there about ten teeth round the margin 

 instead of eight, and they are unequal instead of being equal ; 

 the first two and the last two are long and slender, and the 



17* 



