Naked, or not inclosed in a shell.
11. Cercaria: caudatum. With a tail.
12. Leucophra: ciliatum undique. Every part ciliated.
13. Trichoda: crinitum. Hairy.
14. Kerona: corniculatum. With horns.
15. Himantopus: cirratum. Cirrated, or curled.
16. Vorticella: ciliatum apice. The apex ciliated.
Covered with a shell.
17. Brachionus: ciliatum apice. The apex ciliated.