126 EEPOKT OF COMMISSIONER OF FISH AND FISHERIES. 



New York Harbor, Mr. A. E. Young ; Wood's Holl, Mass. 



There must remain some doubt as to the correct determination of American speci- 

 mens of the present species in the absence of fruit of any Mnd. Sterile specimens of 

 C. roseum are likely to be mistaken for varieties of C. polyspermum or C. Borreri. In 

 C. polyspermum the pinnae are short and subequal, so that the outline of the tips of the 

 branches is linear or oblong, while in C. roseum the pinnae, which are crowded at the 

 ends of the branches are long, gradually diminishing in size towards the apex, so that 

 the plumose tips are pyramidal or broadly ovate in outline. The filaments of C. roseum 

 are finer and more nearly rose-colored than those of C. Borreri, and the pinnae are less 

 regularly distichous. Furthermore, there are no polyspores in G. roseum, and the 

 favellae are not terminal and subinvolucrate as in C. Borreri. All three of the species 

 above named are distinct from the species of the following group in their distichously 

 pinnate ramification, and all three are reddish, inclining to a brownish color. They 

 collapse when removed from the water, but are hardly gelatinous, although all adhere 

 well to paper in drying. 



0. polyspermum, Ag. (G. polyspermum, Phyc. Brit., PI. 231.— Phle- 

 botliamnion polyspermism, Kiitz.) 



Fronds capillary, cortications wanting, two to three inches high, main 

 branches irregularly divided, with few secondary branches below, dis- 

 tichously pinnate above, branches linear or oblong in outline, simply 

 pinnate, pinnae alternate, short, subequal, incurved, upper pinnae some- 

 times pinnulate; tetraspores tripartite, sessile on the upper side of 

 branchlets ; favellae binate near the ends of the branches. 



Hell Gate, N. Y. j Jackson Ferry, Harvey ; Europe. 



The only localities for this species within our limits are the two given by Harvey. 

 We have seen Californian specimens collected by Mr. Cleveland near San Diego, but 

 have never found the plant on the New England coast. The species is related to 

 C. roseum and is distinguished from it by the short, subequal ultimate branches. 



Sect. H. Frtjticosa. 



Growth sympodial, main axis and branches densely corticated : branch- 

 lets pectinate or pinnate, ultimate divisions alternate or secund. 



0. tetragonum, Ag. (G. tetragonum; Phyc. Brit., PI. 136. — G. brachi- 

 atum, Harv., 1. c, PI. 13. — Dorythamnion tetragonum, Kaeg.) 



Fronds monoecious, two to six inches high, coarse and spongy, shrub- 

 like, pyramidal in outline, color dark purple, main filaments densely 

 corticated, smaller filaments monosiphonous ; main axis percurrent, 

 attached by a disk, pinnate with long, undivided, alternate branches, 

 which are once or twice pinnate, the ultimate divisions beset on all sides 

 with short, stout, incurved, acutely pointed, fasciculate branchlets; 

 cells stout, not much longer than broad; antheridia in tufts on the 

 upper internodes; tetraspores tripartite, sessile on the upper branch- 

 lets ; favellae binate. 



Common on stones and algae below low- water mark. 



Long Island Sound ; Europe. 



