Genus MONOSIGA Kent '81.
(Bütschli '86; Francé '97; Senn 1900.)
Small colorless forms of Choanoflagellida, always naked and solitary. The posterior end is attached directly to the substratum, or there is a short stalk not exceeding the body in length. Kent '81 distinguished nine species, but Bütschli questioned the accuracy of many of these, and in this he was followed by Francé '97, who recognized three species—Monosiga ovata, M. fusiformis, and M. augustata. Fresh and salt water.
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Fig. 10.— Monosiga ovata. [ ENLARGE ] |
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Monosiga ovata S. Kent '81. Fig. 10.
Synonyms: M. brevipes S. K.; M. consociata S. K.; M. limnobia Stokes.
The individuals are unstalked or provided with a very short stalk less than the body in length. The form is spherical or ovate, broadest at the base and tapering to the extremity. The collar is somewhat variable in size. In the Woods Hole forms it was about the length of the body. Oil particles present. Contractile vacuole posterior, nucleus anterior.
Fresh and salt water. Length of body without the collar 5µ.
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Fig. 11.— Monosiga fusiformis. [ ENLARGE ] |
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Monosiga fusiformis S. K. Fig. 11.
Synonyms: M. steinii S. K.; M. longicollis S. K.
The individuals are unstalked, minute, and of a general flask-shape. The body is swollen centrally and tapers slightly at each end. There is no stalk, the body being fixed by the attenuate posterior end. There are two contractile vacuoles and one nucleus, which is situated a little above the body center. Fresh and salt water. Length without collar 9µ; length of collar 3µ.