THE MARINE ALG^ OF NEW Els GLAND. 55 



tapering branchlets ; cells .02-8 mm in diameter, those of the mam 

 branches many times longer than broad. 



On stones and covering algae just below low- water mark. Summer. 



Jackson Ferry, N. Y., Harvey; Wood's Holl, Mass. ; Europe. 



One of the longest but at the same time most delicate of the genus. It forms in- 

 tricately branching tufts, one or two feet long, attached to stones, or covers with a soft 

 fleece algae and Zoetera growing in still, shallow bays, like the Little Harbor at Wood's 

 Holl. It is more or less gelatinous and at once collapses on being removed from the 

 water and adheres closely to paper in drying. In drying the cells shrivel very much, 

 and the coloring matter is collected at the ends of the cells, which, in the main 

 branches, are much longer than broad, and on moistening the cells do not recover 

 their shape as readily as in other species. 



C. gracilis, (Griff.) Kiitz. 



Filaments loosely tufted, 3-12 inches long, irregularly bent, provided 

 at the angles with rather short branches, which are pectinate, with long 

 recurved or incurved branchlets; color a yellowish green; cells .04-16 mm 

 in diameter. 



On wharves or in muddy pools. 



New Haven, Prof. Eaton; Wood's Holl, Mass. 



a. Var. EXP ANSA. 



Very irregularly branched, forming masses one to two feet in extent. 



Muddy pools. 

 /§? Gloucester, IsTahant, Mass. 



r 



War. tenuis, Thuret. ( Gl. vadorum, Aresch.) 



Branches remote, filaments more slender than in the type, .04-8 mm in 

 diameter. 

 Growing over Laminarice. 



Gloucester. ? 



A common and variable species, growing in rather muddy sheltered places and not 

 on exposed spots. In its typical form it is recognized by its very irregular branches, 

 which are more divergent than in most other species, and by its pectinate branchlets, 

 which are at times flabellate. The species, although rather delicate in substance, is 

 much stouter than C. albida or C. glaucescens, and does not adhere well to paper. The 

 form which we have referred to, var. tenuis, Thuret, is doubtful. It formed masses of 

 indefinite extent on Laminarice and other algae below low-water mark off Niles's 

 Beach, Gloucester. What we have called var. expansa resembles somewhat C. expanrn, 

 Kiitz., and like it is found in muddy places. It does not, however, form the dense 

 masses of the last-named species, but floats loosely in the water in shallow places. 

 The ordinary forms of the species -are recognized without much difficulty, but one 

 sometimes meets forms which are long and almost denuded of branches, in which case 

 determination is difficult. 



O. EXPANSA, Kiitz. 



Filaments of a dull-green color, at first tufted, then matted together, 

 forming extensive strata; main branches irregularly flexuous, .10-15 mm 



