OF AETS AND SCIENCES. 237 



Agardh PoIi/sipJwnia pecten- Veneris, var. B. Harv,, of the Ner. 

 Am. Bor. II., p. 4G. The question then arises, "VVliat is the plant de- 

 scribed in the Ner. Am. Bor. 11., p. 35, as having but four siphons, and 

 referred to Pohjsiphonia secunda IMont., said by Montagne himself, 

 Syll. Crypt, p. 424, to be the same as P. seciindn Ag. 



PoLYSiPHONiA PENXATA Ag. To this species was doubtfully re- 

 ferred a small Polysiphonia from San Diego, which seemed not uncom- 

 mon on Gelidium cartilagineum and other large Floridece. The 

 specimens should have more properly been referred to Polysiphonia 

 verticillata Harv. A single specimen received from Mrs. T. M. Allen, 

 collected at Santa Barbara, Cal., does not seem to belong either to 

 P. verticillata or to P. dictyurus, if the figure in the Tab. Phyc. is to 

 be trusted, and may belong to Pohjsiphonia pennata. 



Polysiphonia thyrsigera J. Ag. Key West, Mr. F. W. Hooper ; 

 Nassau, Miss Minns. 



Polysiphonia dictyurus J. Ag. San Diego, Cal., Mr. D. Cleve- 

 land. A single specimen, which we supposed to be new and to which 

 we gave the manuscript name of P. Clevelandii, seems to be a variety 

 of P. dictyurns, in which the ramuli are very regularly pinnate, and 

 the ultimate ramuli all beautifully recurved. The number of cells in 

 cross-sections of the larger branches is ten. 



Acanthophora muscoides Ag. The true A. Delilei has never 

 been found in this country. The species given by Harvey with that 

 name, in the Ner. Am. Bor., is Acanthophora muscoides, Ag. and 

 the name A. Delilei should have been suppressed in the Proc. Am. 

 Acad., 1875. 



Ricardia Montagnei Derbes. San Diego, Cal., Mr. Cleveland ; 

 Santa Barbara, Miss Lennebacker. This curious little plant is rarely 

 over quarter of an inch liigh, and grows in small clusters on the con- 

 cave tips of species of Laurencia. The Californian specimens on 

 L. virgata resemble, in all I'espects, those from the Mediterranean, 

 except that tliey are rather more luxuriant. 



Laurencia Brongniartii J. Ag. Key West, Mr. F. W. Hooper. 

 One of the more beautiful species of the genus, and which bears a 

 striking resemblance to Amansia multijida. 



Laurencia tuberculosa J. Ag. Prof. Agardh regards Lauren- 

 cia gemmifera Harv., as a variety of this species. 



Laurencia intricata Lam. Key West, Mr. F. W. Hooper. A 

 species forming dense cushions, and resembling closely the figure in 

 Kiitz. Tab. Phyc, Vol. XV., tab. 61, was collected by Mr. Hooper. 



Laurencia spectabilis, Post. & Rupr. Prof. Agardh is inclined 



