IV. INTEODUCTIOIT. 25 



River, N. C, and at Key West, are all the evidence we at present possess of the 

 existence of that type of form on the North American shore. Plocamium coccineum^ 

 so abundant in Europe, and which is also widely dispersed in the Southern Ocean, 

 extending from Cape Horn eastwards to New Zealand, has not that I am aware of 

 been found on the American Atlantic coast, where its place seems taken by the 

 equally brilliant Rhodymenia cristata. Ceramium rubrum is as common on the 

 American as on the European coast, and many of the other common American 

 Rhodosperms are natives of both continents. 



The Green Alga3 (Chlorosperms) are still more alike ; but several of the Ameri- 

 can CladophoroB (not yet fully explored) seem to be peculiar. Codium tomentosum^ 

 which is common to the shores of Europe from Gibraltar, in lat. 36°, to Orkney 

 in lat. 60°, and perhaps further north, has yet been found only on the Florida Keys, 

 (lat. 24°). Judging fi'om its distribution in other parts of the world, particularly 

 in the Pacific and Southern Oceans, one would have expected to find it all along 

 the East coast of North America. 



Perhaps it would be premature to indicate regions of Algae into which the 

 Eastern and Southern shores of the North American states may be divided, a few 

 points only having as yet been carefully explored. Halifax Harbour, Massachussetts 

 Bay, Long Island Sound at several points from Greenport to New York, New York 

 Harbour, and the neighbourhood of Charleston, S. C, are the chief points at which 

 the materials for this essay have been collected on the East coast. Our knowledge 

 of southern Alg« is at present derived chiefly from a partial examination of the 

 Florida Keys, by Dr. Wurdeinann, Professor Tuomey, Dr. Blodgett and myself I 

 think it probable, however, that future researches will indicate four regions of dis- 

 tribution, as follows : — 



1st. Coast north of Cape Cod, extending probably to Greenland. Among 

 the characteristic forms of this region are the great Laminarias, particularly 

 L. Lo7igic7'uris, one of the largest Algae on the coast, and Agarum Tur7ieri and 

 pertusum. Several of the rarer Fucacese seem also to be confined to this district. 

 One of the most abundant and characteristic species of this tract is Rhodymenia 

 cristata, which has not to my knowledge been found farther south than Cape 

 Cod. Specimens said to have come from Staten Island have been shown to me, 

 but the evidence on which the habitat of these rests is not satisfactory, and 

 none of the Brooklyn and New York Algologists (a numerous and indefatigable 

 band) have yet detected the plant in their harbour. Piilota p)lumosa is also a 

 plant of this region, the only species (as far as I know) that is met with in 

 Long Island Sound being P. sericea, Gm. Rhodomelce are more abundant here 

 than in the Sound, but are not limited to this division ; Odonthalia (a peculiarly 

 northern form) has been seen only at Halifax. Dumontia rameJitacea, so abun- 

 dant at Iceland, is found also at Newfoundland, and near Halifax, where I 

 gathered it plentifully. Of this plant I possess a single specimen, picked up by 

 Miss Frothingham on Rye Beach, New Hampshire. All the species I have men- 

 tioned are Arctic forms confined in the European waters to very high latitudes, 

 and all appear to vegetate nearly as far south as Cape Cod, to which limits they 

 are almost all confined. The Marine flora of this region as a whole bears a 

 VOL. m. art. 4. E 



