OF ARTS AND SCIENCES. 239 



Amphiroa vertebralis D.cne. This form, collected in Oregon 

 by Rev. E. Hull, in 1871, resembles the species described by Postels 

 and Ruprecht as Amph. tuberculosa, Illust. Alg., p. 20, T. XL. fig. 100, 

 and it may be asked whether it is not really the same species. 



Amphiroa Tribclus Lam. A West-Indian species also found at 

 Key West by Mr. F. W. Hooper. 



Amphiroa fragilissima Lam. In the Ner. Am. Bor., Harvey 

 mentions both Amph. fragilissima Lam., and Amph. dehilis K.tg., as 

 found at Key AVest. The Amph. debilis of Kiitzing is, however, only 

 a synonyme for Amph. fragilissima Lam., while the plant refen-ed to 

 by Harvey is a much larger species, possibly Amph. cuspidata Lam. 



LiTHOTHKix AsPERGiLLUM. J. E. Gray. San Diego, Cal., Mr. 

 Cleveland ; Santa Barbara, Miss Lennebacker ; Santa Cruz, Dr. Ander- 

 son, This species seems to be tolerably common along the California 

 coast. It was quoted in the Rep. U. S. Fish Com., 1875, under the 

 name of Amphiroa nodulosa K.tg. Judging from the figure in the 

 Jour. Bot., 1867, there can be no doubt that this is the species there 

 described ; but it is difficult to understand the grounds for separating 

 the genus Lithothrix from Amphiroa. 



Melobesia amplexifroxs Harv. A species which appears com- 

 mon on Zostera, Gelidium cartilagineum, and other algte from Santa 

 Cruz, Cal., southward. The conceptacles are immersed so that the 

 frond appears punctate. 



Melobesia Lexormandi Aresch. San Diego, Cal., Mr. D, Cleve- 

 land. A Melobesia occurs at Wood's Hole, Mass., which is probably 

 also to be referred to this species. 



Melobesia Lejolisii Rosanoff. Common on Zostera at Nahant, 

 Mass. 



LiTHOTHAMXiox POLYMORPHUM Aresch. Very common from 

 Boston northward, forming purple crusts on the rocks in tide pools. 

 Also found at San Diego, Cal. ^ 



LiTHOTH AMNION FASCICUL ATC.M Aresch. Dredged in several places 

 near Eastport, Me. 



Petr'>cklis cruenta Ag. Common on rocks from Nahant, Mass., 

 northward ; also at Santa Cruz, Cal. It has, as yet, been found only 

 with tetraspores. 



Peyssonnklia rubra (Grev.) J. Ag. Tlie species referred to in 

 the Rep. U. S. Fish Comin , 1875, under the name of P. atro-purpurea 

 Crn., belongs more properly to P. rubra. 



Peyssonnelia Dl'byi Crn. San Diego, Cal., Mr. Cleveland. 

 Although P. rubra is common at Key West, it is douDtful whether 



