No. 2] NEW SPECIES OR FORMS OF MELOBESIEAE. 5 



reminds one in habit of young specimens of a form of L. glaciale 

 appearing in shallow water. Besides it now and then approaches 

 L. phymatodeum in habit and even in regard to the conceptacles 

 of sporangia. 



Occurrence. California: Pacific Grove, in low pools, Setchell, 

 No. 1595 and 1596; Duxbury Reef, Marin County, in small pools 

 in the rocks, Setchell, No. 1074 in part; and Puget Sound: Channel 

 Rocks near Seattle, Wash., Setchell and Gardner, No. 654 

 in part. 



Lithothamnion californicum Fosl. 

 Five new calc. Alg. p. 3. 



f. microspora Fosl. mscr. 



Conceptacles of sporangia 200 — 300 p- in diameter seen from 

 above, occasionalfy not raised above the surface of the frond. 



The present species is shown to be rather varying and appears 

 in two different forms rather analogous to Lithothamnion laeve 

 f. macrospora and f. tenuis, partly with large partly with small 

 conceptacles of sporangia. The above f. microspora characterizes 

 itself especially thereby, that the conceptacles of sporangia seen 

 from above are 200 — 300 //. in diameter, thus smaller than in the 

 typical form. They are partly subprominent partly not raised above 

 the surface of the frond, in the latter case at least often caused 

 thereby, that the sporangia for some reason are proportionally 

 more slowly developed than the vegative part of the plant, such 

 as now and then to be seen also in other species. 



The species stands between L. magellanicum and L. tenuis- 

 simum, being very nearly related especially to the latter. It seems 

 even to be a question whether this species ought to be considered 

 specifically distinct from the last named one, which till now is 

 known only from the west coast of Africa. In habit it sometimes 

 much reminds one of L. laeve. 



Occurrence. The form microspora known from Pacific Beach 

 near San Diego, California, collected by Mrs. E. Sn yd er, comm. 

 Mr. F. S. Collins; the typical form is met with in different places 

 along the Pacific coast of America and northward to Puget Sound, 



