1C2 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



On wharves, shells, stones, and sponges below low-water mark, and 

 extending to several fathoms. 

 Cape Cod, southward. 



This, with the exception perhaps of Dasya elegams, is the most beautiful alga of 

 Long Island Sound. It is ofteu found in tufts on wharves below low-water mark, and 

 it flourishes in rather warm, shallow bays. It is met with at all seasons of tbe year; 

 and, according to Miss Fisher, of Edgartown, the ladies of Martha's Vineyard collect 

 it in winter, when it is found in considerable quantities on the ice. Tbe male plant 

 is smaller than the cystocarpic, and the antheridia may be detected by the naked eye 

 in the form of small, whitish, glistening spots. The walls of the conceptacles are 

 thinner than those of Delesseria. The swellings in which the tetraspores are borno 

 can hardly be called warts, and the figure given by Harvey in tho Nereis is somewhat 

 exaggerated. The surface of the frond is raised, and becomes more or less convex, 

 but there are no such irregular projections as represented in Harvey's figure. 



DELESSEBIA, Lam.x. 



(In honor of Baron Benjamin Delessert.) 



Fronds bright red, thin, 'membranaceous, laciniate or branched, cos- 

 tate, and often with lateral veins, composed of a single or a few layers 

 of large r>olygonal cells ; antheridia in spots on the frond ; tetraspores 

 tripartite, grouped in spots (sori) on the frond or on marginal leaflets; 

 cystocarps external, sessile, with a basal placenta, from which radiate 

 the numerous subdichotomous, sporiferous filaments. 



A beautiful genus, comprising fifty or more species, distributed all over tho globe. 

 They are of delicate texture and rosy-red color, and are generally leaf-like in appear- 

 ance, although some are narrowly linear. The genus is not likely to be mistaken for 

 any other on our coast, unless it be Grinnellia, in which the tetraspores are borne in 

 thickened portions of the frond. The fronds, when young, are more or less leaf-like 

 and provided with a midrib, and generally also with lateral nerves ; and, as they 

 grow older, they become more or less stipitate by the wearing away of the blade of 

 the leaf, which leaves the thickened midrib either naked or with a small winged 

 margin. When still more advanced, owing to the growth of the laciniaj and the 

 wearing away of the lateral nerves, the stipes appear to branch and to bear several 

 leaf-like fronds. In some species the membranous portion of the fronds consists of a 

 single layer of cells, which are rectangular when seen iu section and polygonal seen 

 from above. At the veins the cells form several layers, and in some species it is only 

 at the tip that tho fronds are formed of a single layer. When the cystocarps are 

 formed, the cells are divided by numerous partitions parallel to the surface of the 

 frond, and the wall of the conceptacle, when mature, consists of several layers of cells, 

 all of about the same size and smaller than the cells of tho frond. 



D. siNTJOSA, Lam.x. ; Phyc. Brit., PI. 259. 



Fronds four to eight inches long and two to four broad, stipitate be- 

 low, stipe often elongated and branched, with oblong or obovate, deeply 

 sinuate or pinnatifid toothed leaves, midrib percurrent, lateral veins 

 opposite, extending to the lacunae ; tetraspores tripartite, either borne in 

 small lateral leaflets or in patches following the veins ; cystocarps ses- 

 sile, generally en the veins, hemispherical, with a distinct carpostome. 



On algae, generally in deep water. 



