Genus GLENODINIUM (Ehr.), Stein '83.

(Bergh '82; Bütschli '86; Pouchet '85; Daday '86.)

Small globular forms with two distinct furrows, one transverse around the body, the other longitudinal upon the face only. The shell is soft and structureless with a distinct aperture near the meeting point of the two furrows. The endoplasm usually, but not always, contains a bright red eye-spot.

Fresh and salt water.

Glenodinium compressa, n. sp. Fig. 21, a, b, c.

This species resembles G. acuminata of Ehrenberg except that it is strongly compressed laterally. The longitudinal furrow extends nearly to the extremity of the animal. It begins as a narrow slit and widens as it progresses upon the left side; it also becomes much deeper on this side and at the bottom of the depression the longitudinal flagellum is inserted. The transverse furrow runs evenly around the body near the upper pole, giving to the shell almost the aspect of an [Amphidinium]. Brown chromatophores may or may not be arranged radially about a central amylum granule. One striking characteristic is the depth of the two furrows. The nucleus is elongate and somewhat curved; it lies against the posterior wall of the rather thick shell. Not uncommon.

Length 40µ; breadth 32µ; width 18µ.

The posterior end of the animal is often somewhat pointed and this point frequently becomes attached, so that the animal whirls around upon it as upon a pivot.


Fig. 21 a, b, c.—Glenodinium compressa, n. sp.
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Glenodinium cinctum Ehr. Fig. 22.


Fig. 22.—
Glenodinium cinctum.

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The body is globular, smooth, and homogeneous. Brown chromatophores arranged radially, each in the form of a cone, the base of which rests against the shell while the points turn inward. A bright-red eye-spot may or may not be present; when present it is placed near the junction of the two furrows. The longitudinal furrow is small. Fresh water and salt.

Length and diameter the same, 21µ.

This species was observed by Peck '93.

[Illustration: Fig. 22.—Glenodinium cinctum.]