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.


[Illustration: Fig.10.--_Monosiga ovata_.]


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.


[Illustration: Fig. 11.--_M. fusiformis_.]