3. Volvox: sphæricum. Spherical.
4. Enchelis: cylindraceum. Cylindrical.
5. Vibrio: elongatum. Long.
Membranaceous.
6. Cyclidium: ovale. Oval.
7. Paramæcium: oblongum. Oblong.
8. Kolpoda: sinuatum. Crooked, or bent.
9. Gonium: angulatum. With angles.
10. Bursaria. Hollow like a purse.
II. THOSE THAT HAVE EXTERNAL ORGANS.