698 
Transactions of the Society. 
as long as the body. Hab. pond water ; attached to the rootlets 
of Lemna. Solitary. 
This form most nearly approaches the Monosiga obovata described 
by the writer, but is readily distinguishable by its smaller size, the 
proportion borne by the length to the width, and the presence of two 
contractile vesicles. 
Monosiga filicaulis. Fig. 2. 
Body broadly ovate, the length but little greater than the width, 
slightly changeable in shape, elevated upon a delicately filiform pedicle 
from ten to twelve times as long as the zooid; contractile vesicles 
two, placed near the centre of the opposite lateral borders, a vacuole 
developed close to the posterior extremity. Length of the body, 
1/1800 in. Hab. pond water; attached to the rootlets of Lemna. 
Solitary. 
This is distinguishable from the Monosiga longipes of the author 
by the different form of the body, the smaller size and the much 
greater proportionate length of the pedicle. 
Salpingoeca brunnea. Fig. 3. 
Lorica vasiform, the body or main portion sub-hemispherical, 
somewhat depressed, the neck almost as long as the height of the sub- 
spherical portion, the anterior margin flaring ; body of the lorica 
usually a deep, chestnut brown in colour, while the neck -like pro- 
longation is entirely colourless; inclosed organism not entirely 
filling the lorica, projecting some distance beyond the anterior aper- 
ture. Length of lorica about 1/600 in. Hab. pond water. 
This beautiful form is not rare in the writer’s vicinity, and it is 
specially noteworthy for the deep chestnut-brown colour of the body 
of the lorica and the colourless condition of the neck. How speedily 
after its formation the lorica assumes this tint is not known ; I have 
not seen a colourless specimen. 
Plagiopyla Hatchi. Fig. 4. 
Body elongate-obovate, somewhat depressed, soft and flexible, less 
than three times as long as broad, the anterior border often obliquely 
rounded, the posterior extremity somewhat tapering and subacutely 
pointed ; right-hand lateral margin frequently flattened, the left-hand 
side convex ; oral aperture ovate, situated in the anterior body-half, 
near the right-hand body margin, its right-hand border bearing a 
narrow, undulating membrane ; pharynx obscure ; nucleus ovate, sub- 
centrally placed ; contractile vesicle single, spherical, near the centre 
of the right-liand body margin ; cilia numerous, fine ; trichocysts 
abundant, placed perpendicularly to the cuticular surface, which is 
minutely papillose. Length of body 1/150 to 1/200 in. Hab. 
ponds and standing water near Minneapolis, Minn. 
