Diagnostic characters: Body attached by a stalk to a cup. Inside the
zone of membranelles is a ring of cilia (par-oral).
1. The test is gelatinous and more or Genus _Tintinnidium_
less covered by foreign particles
2. The test is chitinous and clear. Genus _Tintinnus_
No foreign particles.
3. The test is chitinous; covered by Genus *_Tintinnopsis_
foreign particles, growth rings
frequent
4. The test is chitinous, often Genus _Codonella_
covered by foreign particles.
The test is marked by discoid,
circular, or hexagonal spots.
5. The test is perforated by pores Genus _Dictyocysta_
of circular or hexagonal form.
* Presence at Woods Hole indicated by asterisk.
Genus TINTINNOPSIS Stein '67.
(Stein '67; Kent '81; Daday '87; Bütschli '88.)
Medium-sized ciliates, inclosed in a chitinous lorica with embedded
sand crystals. The form of the house, or lorica, varies greatly.
In some cases the mouth opening is wide, giving the lorica a bell
form; it may be long and tubular, short and spherical, or variously
indented. The animal is attached, as in the closely allied genus
_Tintinnus_, by a peduncle to the bottom of the lorica. The anterior
end of the animal is inclosed by two complete circles of cilia;
one, the outer, forming the adoral zone, is composed of thick
tentacle-like membranelles, the other consists of shorter cilia
within the adoral zone. The mouth leads into a curved oesophagus
containing rows of downward-directed cilia (Daday). The entire body
is covered with cilia, but as the lorica is always opaque these can
be made out only when the animal is induced to leave the house. The
only difference between this genus and _Tintinnus_ is the covering
of foreign bodies--usually sand crystals. Movement is rapid and
restless, and peculiarly vibratory, owing to the apparent awkwardness
in moving the house. Salt water.
Tintinnopsis beroidea Stein, var. plagiostoma Daday. Fig. 47.
Synonym: _Codonella beroidea_ Entz '84.
The shell is colorless, thimble-shaped, with a broadly rounded
posterior end. The body is cylindrical. The internal organs were not
observed. Membranelles 24 in number. Length 50µ; greatest diameter
40µ.
[Illustration: Fig. 47.--_Tintinnopsis beroidea_.]
Var. compressa Daday '87.
The posterior end of the shell is pointed, the lower third of the
shell is swollen, the upper third is uniform in diameter and without
oral inflation or depression. Nucleus not seen.
Length 70µ; greatest diameter 48µ.
Tintinnopsis davidoffi Daday. Fig. 48.
The shell is large, elongated, and provided with a considerable
spine. The chitin of the shell is covered with silicious particles of
diverse size. The internal structures were not observed.
Length of shell and spine 230µ; diameter of the oral aperture 54µ.
[Illustration: Fig. 48.--_Tintinnopsis davidoffi_.]
The variations of these species are considerable, and as the internal
structures, such as the nucleus, are essential in fixing their
systematic position, I place them as above, provisionally, and until
further observations can be made.