LIST OF THE SEA-WEEDS OR MARINE ALG^, ETC. 291 



C3. C. rosea, {Chrysimcjiia, Phye. Britt.,) Harv. This rare and beau- 

 tiful alga I have found only by dredging in tlie region of the 

 Devil's Back, Gay Head, in eight or ten fathoms. The tetra- 

 spores only were found. 



Spyridiace^. 



64. Spyridia filamentosa, Harv. Common on eel-grass at Wood's 



Hole, Waquoit, Weepecket, and Greenport. 



Ceramiace^. 



65. Ceramium ruhrnm, Ag. Common everywhere. 



CO. C. diaphanum, HoTH.. Common and luxuriant on eel-grass. Wood's 

 Hole, Weepecket, Edgartown. 



67. C fastigiatiim, Harv. Common on eel-grass in August and Sep- 

 tember at Wood's Hole, Weepecket, Newport, Orient, and 

 Greenport. 



08. C. arachnoideion, (?) Ag. Wood's Hole, Orient Point. There 

 grows in abundance on fiici, at Wood's Hole, a Ceramium 

 without fruit of either kind in September. It grows in long 

 Ijatches on the stems of fiici near low-water mark. The fila- 

 ments are rather robust, not more than an inch long, scarcely 

 branching and forcipate at the tip. The internodes are di- 

 aphanous, and I am not certain that it is not a young state of 

 C. diaplianum. At any rate I will not confuse an already suffi- 

 ciently subdivided genus by adding a doubtful species. 



69. Ptilota eJegans, Bonnem. Common between Gay Head and No 



Mans Land, Newport. Wherever found, abundant. 



70. Grijffithsia corallina, Ag. This charming iilant is not uncommon 



during July in Buzzard's Bay, Wood's Hole, and Weepecket 

 Islands; at the latter station I have seen the water full of it. 

 Var. glob if era 1 have found only on the Government Wharf, 

 Wood's Hole, and once or twice in Buzzard's Bay. It is coarser 

 in color and texture, and is not so easily dried on paper as the 

 ordinary form. If merely a variety, it seems to owe its form to 

 its exposed place of growth. 



71. Callithamnion tetragonum, Ag. Wood's Hole, Martha's Vineyard, 



Newport. Common on the larger algte and wood-work just 

 below low-water mark. 



72. C. Baileyi, Harv. Not to be distinguished, in my opinion, from 



C. tetragonum, except by being less robust and somewhat more 

 compoundly branched. It seems to me to be merely a variety 

 grown early in the season while the water is warm. 



73. C. Borreri, Ag. Greenport, Wood's Hole. My specimens are 



softer than European, and seem too near C. j)olyq)ermum. 



