2. Flagellum never thrown off 3

3. a. Pseudopodia lobose Genus _Mastigamoeba_

b. Pseudopodia ray-like Genus _Mastigophrys_

Family _Codonoecidae_:

1. Goblet-shaped cups adherent Genus *_Codonoeca_ by stalk

Family _Heteromonadidae_:

1. The long flagellum vibratory Genus *_Monas_

2. The long flagellum rigid; Genus _Sterromonas_ shorter one vibrates

* Presence at Woods Hole indicated by asterisk.

KEY TO MARINE QENERA OF CHOANOFLAGELLIDA.

1. Without gelatinous 3 or membranous test

2. With gelatinous 4 or membranous test

3. a. Attached forms:

1. Without a stalk, or with Genus *_Monosiga_ a very short one

2. With a long, simple, stalk Genus *_Codonosiga_

3. With a long, branched, stalk Genus _Codonocladium_

b. Free-swimming Genus _Desmarella_

4. Colonial, and with a gelatinous Genus _Proterospongia_ covering

* Presence at Woods Hole indicated by asterisk.

KEY TO FAMILIES AND MARINE GENERA OF HETEROMASTIGIDA.

1. Two flagella nearly equal in size Family _Bodonidae_

One main and 2 accessory flagella Family _Trimastigidae_

Family _Bodonidae_:

1. Body very plastic, Genus *_Bodo_ almost amoeboid

Body not plastic; with large Genus *_Oxyrrhis_ anterior cavity, holding flagella

Family _Trimastigidae_:

1. With an undulatory membrane Genus _Trimastix_ between accessory flagella

Without such membrane; flagella Genus _Costia_ contained in a ventral groove while at rest

* Presence at Woods Hole indicated by asterisk.

KEY TO MARINE GENERA OF POLYMASTIGIDA.

1. Body flattened; ends rounded; Genus _Trepomonas_ sides hollowed; often with wing-like processes; cross section S-shaped

2. Body pyriform; one large Genus _Tetramitus_ asymmetrical groove; 4 flagella

3. Body spherical; many flagella Genus _Multicilia_ equally distributed

KEY TO FAMILIES AND MARINE GENERA OF EUGLENIDA.

1. With deeply-insunk pharynx; 2 no mouth

With pharynx and distinct mouth Family _Peranemidae_

2. Body plastic; usually with Family _Euglenidae_ chromatoph.o.r.es and eye-spot

Body plastic; no chromatoph.o.r.es; Family _Astastidae_ no eye-spot

Family _Euglenidae_:

Body _Euglena_-like, inclosed Genus _Trachelomonas_ in sh.e.l.l with round opening for exit of flagellum

Family _Astastidae_:

Body with one flagellum Genus *_Astasia_

Family _Peranemidae_:

1. Body striped; plastic; Genus _Heteronema_ two diverse flagella

2. Body striped; not plastic; Genus *_Anisonema_ posterior flagellum longer than the other

3. Body striped; not plastic; Genus _Entosiphon_ with rod-like organ in pharynx

* Presence at Woods Hole indicated by asterisk.