118 EEPOET OF COMMISSIONER OF FISH AND FISHERIES. 



A small genus, containing at the most only four or five species, of which S. furcel- 

 lata is widely distributed. The genus is uftmistakable on microscopic examination by 

 the slender axis and large colorless cylindrical cells which cover the surface of the 

 fronds, and by the peculiar cystocarps which are visible to the naked eye as dark red 

 grains just under the surface. The species should be studied from living or alcoholic 

 specimens, since, owing to the delicate substance, pressed specimens are badly dis- 

 torted. 



S. furcellata, Bivona. (Ginannia furcellata, Mont.; Phyc. Brit., 

 PL 69. — S. furcellata, Notes Algologiques, PL 6.) 



Fronds solitary or clustered, cylindrical, rising- from a disk-like base, 

 several times dickotouious, divisions regular, apices obtuse. 



On stones and shells in five to ten fathoms. 



Newport, E. I., Bailey ; Gay Head, Mass., W. G. F. 



A rare species with us, but widely distributed throughout the world, being found in 

 most warm seas. In size and regularity of its dichotomous branching it resembles 

 Polyides rotundas, but is much more delicate in substance and brighter colored. With 

 us it is only known at a considerable depth and in rather cold waters, but in the Med- 

 iterranean it is frequent in warm shallow waters. It is not uncommon on shells of 

 Mytilus near the Devil's Bridge, Vineyard Sound, Mass., and is found washed ashore 

 in the neighboring beach of Gay Head. The Californian form of wbat is supposed to 

 be the same species is much more robust, and the var. itndulaa, which Montague con- 

 sidered a distiuctspecies, is somewhat compresed and constricted at intervals. When 

 pressed the specimens are quite flat and the axis is plainly seen, giving the appearance 

 of a membranous frond with a midrib. 



Suborder SPERMOTHAMNIE^. 



Fronds filamentous, monosiphonous, branching ; antheridia tufted ; 

 cystocarps involucrate, spores borne free on the surface of a lobulated 

 mass produced by the carpogenic cells. 



In this suborder we would place Spermothamnion and Bornetia, separated from Cal- 

 lithamnion and Griffithsia, respectively, in consequence of the spores being borne free. 



SPERMOTHAMNION, Aresch. 



(From orrepua, a seed, and dapviov, a small bush.) 



Fronds tufted, composed of procumbent monosiphonous filaments 

 attached to the substratum by disk-shaped cells and vertical branching 

 filaments ; antheridia sessile on the inner side of the branches, composed 

 of oval or cylindrical masses of small cells ; cystocarps terminal on the 

 branches, surrounded by an involucre of short incurved branchlets, spores 

 free from one another and not surrounded by a gelatinous envelope ; 

 tetraspores tripartite, single or aggregated, borne on the inner side of 

 the branchlets. 



A small genus, comprising, as far as known, less than half a dozen species, separated 

 from Callithamnion because the spores at maturity are borne free on the surface of a 

 lobulated mass which arises from the development of the carpogenic cells, and not, as 



