176 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



in a double row in terminal fusiform branches (stichidia) ; cystocarps 

 terminal on the branches, ovate, wfth a distinct carpostome, spores piri- 

 form, attached to short filaments which are given off from a basal pla- 

 centa. 



A genus of about twenty species, characterized by their lurid purple color and by grow- 

 ing in places where the water is not very salt, some species, it is said, even growiug 

 in fresh water. They inhabit principally the tropics. The genus is intermediate 

 between Polysiphonia and Dasya, and some species have been previously referred to 

 Ehodomela. The tetraspores are in stichidia, as in Dasya, but the cystocarpic spores 

 seem to us more nearly like those of Polysiphonia. The frond is originally nionosipho- 

 nous, aud soon becomes polysiphonous, the number of siphons not being as constant 

 as in Polysiphonia. The corticating cells, when present, are regularly arranged in 

 transverse bands. The development of the frond has been studied in detail by Dr. 

 Ambroun in B. scorpioides. 



B. rivularis, Harv., jSer. Am. Bor., Part II, PI. 14 d. 



Exs. — Alg. Am. Bor., Farlow, Anderson & Eaton, No. 54. 



Fronds an inch high, capillary, rising from a procumbent base, branches 

 flexuous, bipinnate, pinnae distichous, alternate, patent, loosely pinnu- 

 late, pinnules subulate, section of main branches showing about seven 

 siphons; tetraspores cruciate, in two rows in oblong stichidia below 

 the tips; cystocarps ovate, terminal on the shortened, naked, lower 

 pinnae. 



On submerged logs in patches. 



Hell Gate, N. Y., Harvey; Fort Lee, K Y., Mr. Averill; College Point, 



Astoria, C. H. Peck; common southward; Australia. 



A common species from Charleston, S. C, southward, but only occasionally found 

 with us. The only certain localities are near New York City, and it is extremely 

 doubtful whether it was ever found in the arctic waters of the Isle of Shoals, where 

 it was reported by Captain Pike. The species is small and rather insignificant, but 

 is easily recognized by its polysiphonous structure and ramification. There are no 

 cortications, and the species belongs to the subgenus Stictosiphonia. 



DASYA, Ag. 



(From 6aovQ, hairy.) 



Fronds bright red, filiform or compressed, distichously or irregularly 

 branching, composed of a monosiphonous axis surrounded by several 

 (4-12) siphons, often corticated with irregularly shaped cells, clothed in 

 the upper part or throughout with colored, monosiphonous r dichoto- 

 mous branchlets; antheridia in siliculose tufts on the branchlets; tetra- 

 spores tripartite, borne in regular rows in lanceolate or ovate-lanceolate 

 enlargements of the branchlets ; cystocarps ovate, acuminate, sessile 

 or pedicellate, spores terminal on branching filaments arising from a 

 basal placenta. 



A largo and beautiful genus, including aboutseventy species, of which the greaterpart 



