of the larger one. The nucleus is usually anterior, and one or two
contractile vacuoles are present.


Monas sp. Fig. 9.

An extremely small form (3µ) attached by a thread of
protoplasm--perhaps a flagellum, to algæ. The body is ovoid and
the main flagellum is about four times the length of the body. The
contractile vacuole is posterior. Only one specimen was seen and
upon this I shall not attempt to name the species.


[Illustration: Fig. 9.--_Monas_ sp.]


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.


Monosiga ovata S. Kent '81. Fig. 10.