REVIEWS. 15 



the Algae ; from all these heads we would gladly extract, did our space 

 permit ; we must, however, confine ourselves to a brief notice of the u Four 

 regions of distribution" into which it is proposed to divide (for the pre- 

 sent) the eastern and western shores of the United States. 



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

 Among the characteristic forms are, Laminaria Longicruris (one of the 

 largest on the coast), Agarum Turneri, and pertusum, Rhodymenia 

 cristata, Ptilota plumosa, and Dumontea ramentacea. All the species 

 mentioned are northern forms, and confined, in European waters, to 

 very high latitudes, and all appear to vegetate south nearly, as far as Cape 

 Cod, to which limits they are almost all confined. The marine flora of 

 this region, as a whole, bears a resemblance to the shores of Iceland, Norway, 

 Scotland, and the north and north-west of Ireland. 



2nd. Long Island Sound, including under this head, New York 

 Harbour, and the sands of New Jersey. In comparing the plants 

 of the Sound with those of the first region, a marked difference is 

 observable. We lose the Arctic forms, and their place is supplied by 

 Sargassum, two species, by various beautiful Callithamnia and Poly- 

 siphoniaj, and by abundance of Delesseria Americana, and Dasya 

 elegans, Seirosiphora Griffithsiana is not uncommon, Rhabdonia Baileyi, 

 Gracilaria multipartita (narrow varieties), Chrysemenia divaricata and 

 C. Rosea are also characteristic forms, Delesseria Leprieurii also belong 

 to this region, but it is a tropical form, at its utmost limit of northern 

 distribution. 



3rd. Cape Hatteras to Cape Florida. Many species found within 

 these limits are common to those found in the second region ; others are 

 here met with for the first time, as Arthrocladia villosa and a Nito- 

 phylhim, found at Wilmington ; a noble Grateloupia, probably new (G. 

 Gibbesii, MS.), and Delesseria hypoglossum. I have seen no Fucoid 

 plant from this region ; but if there were a suitable locality here, we ought 

 to have Sargassa ; all the estuaries of the district produce Grate- 

 loupia Gibbesii, and a Bostrychia, either B. radicans Mont., or a 

 closely allied species. These last are tropical forms, first observed at 

 Cayenne. 



4th. Florida Keys and Shores of the Mexican Gulf. — Here we 

 have a very strongly marked province, strikingly contrasted in vegetation 

 with the east coast, mentioned in the three regions already noticed. Of 

 130 species collected at the east coast in February, 1850, scarcely one- 

 eighth are common to the east coast, seven-eighths being unknown to the 

 American coast north of Cape Florida. With this remarkable difference 



