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REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 117
Nemalion the procarp consists of a short branch composed of a few cells, the upper of which enlarges
and bears a hair-like trichogyne. The fruit in Nemalion has no special covering, but in Helminthora and
Helminthocladia the lower cells of the procarp produce whorls of filaments which form an involucre
around the spores, and in Scinaia they produce a membranous sack which opens at the apex, so that
when ripe the fruit consists of a conceptacle opening outwards, at whose base is borne a tuft of spores
arranged in filaments. With regard to the tetraspores in the present suborder, a difference of opinion
exists. Contrary to what is found in other Florideæ, the cystocarpic individuals are common, whereas
tetrasporic individuals are unknown except in Nemalion, in which genus, on the authority of Agardh,
they are borne in the superficial cells and are tripartite.
NEMALION, Duby.
(From νηµα [nema], a thread.)
Fronds gelatinous, cylindrical, solid, repeatedly dichotomous, cortical filaments
corymbose, giving off descending branches, which unite with the axial filaments;
antheridia in tufts on the superficial cells; procarps borne at the base of the
corymbose branches, consisting of few cells; cystocarps immersed, without special
covering, sporiferous filaments radiating from the trichophore; “tetraspores
tripartite in the superficial” cells. (Agardh.)
A small genus, comprising seven or eight species, only one of which, N. multifidum, is widely diffused.
N. MULTIFIDUM, Ag., Phyc. Brit., Pl. 36. (Mesogloia multifida, Ag., Syst.) Pl. 12, Fig.
1.
Fronds brownish purple, lubricous, two to eight inches long, cylindrical, several
times dichotomous, axils obtuse.
On exposed rocks at low-water mark. Summer.
From Watch Hill, R. I., northward; Europe.
Not uncommon on rocks exposed to the action of the waves. Commonly found with cystocarps, but no
tetraspores have been seen on American specimens. In the Nereis the species is said to have been
collected at Bangor, Maine, by Mr. Hooper. This must be an error, however, since Bangor is on the
Penobscot River, above the limit of salt water. Specimens of the present species are so gelatinous as to
dry with difficulty. They should be exposed in the air for two or three hours before pressing.
SCINAIA, Bivona.
(In honor of Domenico Scina, of Palermo.)
Fronds subgelatinous, dichotomous, cylindrical or compressed, axis small, composed
of slender colorless filaments, horizontal filaments ending in short corymbs of small,
round, colored cells, the centers of all the corymbs bearing large, colorless,
cylindrical cells, which by their juxtaposition form an epidermis over the whole
frond; antheridia in small tufts on the superficial cells; cystocarps borne just below
the cortical layer, consisting of membranous sacks opening externally, with a tuft of
spore-bearing filaments attached to the base; tetraspores unknown.