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.