2. Spongia ostracina, Raf. (Oyster sponge.) Very branched, erect, red, papillose; branches unequal, often dichotome, obtuse; cells porose, oblong, nearly equal.
It is often found on the common oyster. (Ostrea virginica.) It rises from four to six inches, the colour is a fine red, it branches from the base; the branches are unequal, straight, cylindrical, or compressed. Substance stupose. Surface covered with small papilla and small oblong unequal pores.
3. Spongia cespitosa, Raf. (Bushy sponge.) Branched, cespitose, yellowish, rough, papillose; branches fasciculated, upright, unequal, flexuose, compressed, slightly anastomosed, nearly dichotome upwards; cells porose, oblong, nearly equal, margin lacerated.
Found also on the oyster, but more seldom than the foregoing; the specimens which I saw was found on the Bluepoint oysters, by Dr. Eddy. It becomes brown by drying. It rises from four to six inches, the margin of the cells or pores is torn into papillar, stiff processes, which produce a rough surface. Substance stripose. Internal cells oblong, very small.
4. Spongia cladonia. (Cladonian sponge.) Branched effuse, smooth, pale fulvous, stem procumbent, branches distichal, one-sided, erect, simple or divided, obtuse; cells porose, minute; some larger round.
I have found this species at Bath and at Sandy-Hook, on Sandy bottoms. Length about six inches. Stem and branches cylindrical or compressed. Substance fibrose, anastomed, branches divaricate, ascendent, semi dichotomose or simple, unequal, thicker towards the top.
5. Spongia virgata. (Slender sponge.) Nearly branched, smooth, fulvous, stem divided, slender, cylindrical, knobby, branches erect, slender, nearly heads acute; pores unequal, irregular, small.
A small species, three inches high, found at Oysterbay, on rocky bottoms, rare; stem with few branches, and imperfect ones, like knobs. Substance stupose. Branches round, alternate, small. Pores without any determinate shape.