Marine Protozoa from Woods Hole | Page 8

those of the
longitudinal furrow usually form great, lateral, wing-like processes
ornamented by ribs and other markings.
1. Without shell; longitudinal Genus *Amphidinium furrow may open
& close
2. With shell; longitudinal furrow 3 unchangeable
3. With distinct apical funnel 4
No apical funnel Genus Phalacroma
4. With great wing-like ledge 5

Ledges very small; body long, Genus Amphisolenia needle-like
5. Ledge of longitudinal furrow 6 extends to posterior end
Ledge of longitudinal furrow Genus Dinophysis does not extend to
posterior end (Recorded by Peck ('93-'95) as very abundant at Woods
Hole and in Buzzards Bay.)
6. Ledge is continued dorsally to Genus Ornithocercus the cross-furrow
Ledge is not continued dorsally 7
7. With deep dorsal cavity; Genus Citharistes secondary funnel not
notched
No dorsal cavity; secondary Genus Histioneis funnel deeply notched
* Presence at Woods Hole indicated by asterisk.
Genus EXUVIÆLLA Cienkowsky '82.
(Klebs '81; Pouchet '83, '86.)
The form varies from globular to ovoid, with occasionally a sharp
posterior end. Shells are usually somewhat compressed, and consist of
two valves, which frequently slide one over the other in such a manner
as to show the structure with great clearness. The right shell may have a
distinct indentation in the anterior edge. There are two lateral, discoid,
brown chromatophores, each of which possesses a central amylum
granule. The nucleus is posterior. Salt water.
Exuviælla lima Ehr. Fig. 18.
Synonyms Pyxidicula Ehr.; Cryptomonas Ehr.; Prorocentrum lima
Kent; Amphidinium Pouchet.
The shell is ovate, rounded and swollen posteriorly. The anterior border
of both shells is slightly indented. The shell is quite thick. The animal
moves through the water very slowly. Dark brown in color. Length 48µ;

width 44µ.
[Illustration: Fig. 18.--Exuviælla lima.]
Exuviaella marina Cienkowsky. Fig. 19.
A smaller form than the preceding, more elliptical in outline, with a
thinner shell and with large granules throughout the endoplasm. The
nucleus is spherical and subcentral in position and possesses a distinct
central granule. This may be a small variety of E. lima.
[Illustration: Fig. 19.--Exuviælla marina.]
Genus GYMNODINIUM Stein '78.
(Bergh '81; Kent '81; Pouchet '83, '85; Entz '84; Schütt '95.)
The general structure of these forms is similar to that of Glenodinium;
the most striking and positive difference is the absence of a shell. The
animals are, as a rule, spherical, yet they may be pointed at the two
ends or at one of them. They are also frequently flattened
dorso-ventrally. The transverse furrow may be either circular and
straight around the body or may describe a spiral course, passing even
twice around the body. The flagella arise near cross-furrow or, in some
cases, in longitudinal furrow. Chromatophores may or may not be
present and food-taking is holozoic, in many cases at least. In some
cases ectoplasm and endoplasm can be distinguished. Fresh and salt
water.
Gymnodinium gracile Bergh '82, var. sphærica, n. Fig. 20.
The body is divided by the transverse furrow into a shorter anterior and
a longer posterior part. The longitudinal furrow is broader at the
posterior extremity than at the cross-furrow. The structural feature upon
which this new variety is made is the unvarying plumpness of the body,
making it almost spherical, except for a slight flattening dorso-ventrally.
The nucleus is large and ellipsoidal, with characteristic longitudinal
markings of chromatin. The endoplasm is evenly granular, with a

number of large ingested food bodies. The color is brown, not rose-red
as in Bergh's species, nor is the Woods Hole form as large as the latter.
Length of body 68µ; width 55µ. Common.
[Illustration: Fig. 20.--Gymnodinium gracile, var. sphærica.]
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