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REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 69
would, however, incline one to consider that the antheridia in this genus were not proper male bodies.
Some of the species of Ectocarpus described by Harvey in the Nereis were founded on sterile specimens,
but, at the present day, algologists agree in thinking that the presence of sporangia is necessary for the
determination of species of Ectocarpus, and we have, accordingly, omitted the Harveyan species
founded on sterile plants as being inadequate.
SUBGENUS STREBLONEMA, Derb. & Sol. (Entonema, Reinsch).
Primary branches procumbent, creeping in or over the substance of other algæ;
secondary and fructifying ramuli erect.
E. CHORDARIÆ, n. sp.
Filaments much branched, irregularly nodose, about .02 mm in diameter, sunk in the
tissue of the host-plant; hairs and fertile branches erect, the former projecting above
the surface; unilocular sporangia on short stalks, solitary or clustered, oval, about
.07 mm broad by .14 mm long; plurilocular sporangia unknown.
Parasitic in the fronds of Chordaria divaricata, Leathesia tuberiformis, and other
Phæosporeæ.
Wood’s Holl, Gloucester, Mass.; Newport, R. I.
A common- but insignificant species which grows in the cortical portion of different Phæosporeæ,
especially Chordaria divaricata, and usually in company with Bulbocoleon. It forms dark-colored spots
on the surface of the plant in which it is growing, and, on a hasty microscopic examination, would pass
unnoticed, so great is the resemblance of the sporangia to those of Chordaria. Our plant resembles S.
sphæricum, Thuret, but differs from the Mediterranean forms of that species in having oval, not
spherical, sporangia, which are often clustered. The filaments, too, are composed of very irregularshaped
cells, and are never moniliform as in well-developed specimens of S. sphæricum. It may,
however, be the ease that what we have considered specific marks are only local variations. It may also
be asked whether the present species is not the form of S. fasciculatum, Thuret, which bears unilocular
sporangia. At present only the plurilocular form of sporangium is known in that species as it occurs in
Europe.
E. REPTANS, Crouan, Florule du Finistère, p. 161; Kjellman, Bidrag till Känn. Skand.
Ect. Tilop., p. 52, Pl. 2, Fig. 8,
Filaments forming circular spots on the host-plant, primary branches very densely
branching, so that they almost form a membrane, furnished with numerous erect
branches, which are .5-7 mm high and gradually taper to a hyaline hair; cells at base
about .0l mm broad; plurilocular sporangia arising from the primary filaments, sessile
or on short stalks, ovate-acute, .012-20 mm broad by .038-76 mm long.
On Phyllitis and Dictyosiphon. Summer.
Newport, R. I.; Europe.
A larger species than the preceding and growing more superficially, so that the filaments may be said
to creep over the surface rather than in the substance of the host-plant. Owing to the dense branching
of the prostrate filaments and the abundance