[Ill.u.s.tration: Fig. 4.--_Gromia lagenoides_.]

Genus TRUNCATULINA D'Orbigny.

A group of extremely variable foraminifera in which the sh.e.l.l is rotaline; i. e., involute on the lower side and revolute on the upper (Brady). The sh.e.l.l is calcareous and coa.r.s.ely porous in older forms.

The characters are very inconstant, and Brady gives up the attempt to distinguish the group by precise and constant characters.

Truncatulina lobatula Walker & Jacob.

Synonyms: See Brady '84 for a long list.

"It is impossible to define by any precise characters the morphological range of the present species. Its variations are infinite." (Brady, p. 660.)

This very common form, which occurs in all lat.i.tudes, was found frequently among the algae at Woods Hole. Its characters are so difficult to define that for the present I shall limit my record to this brief notice. Size of sh.e.l.l 230 by 270.

Genus ACTINOPHRYS Ehr.

The body is spherical and differentiated into granular endoplasm and vacuolated ectoplasm, but the zones are not definitely separated.

There is one central nucleus and usually one contractile vacuole. The pseudopodia have axial filaments that can be traced to the periphery of the nucleus. Fresh and salt water.

Actinophrys sol Ehr., variety. Fig. 5.

Synonyms: See Schaudinn '95.

The diameter is about 50; the vacuolated ectoplasm pa.s.ses gradually into the granular endoplasm. This is the characterization given _A.

sol_ by Schaudinn, and it applies perfectly to the freshwater forms.

If I am correct, however, in placing an _Actinophrys_-like form found at Woods Hole in this species, the description will have to be somewhat modified. In this form (fig. 5) there is no distinction between ectoplasm and endoplasm, and there is an entire absence of vacuoles. The nucleus is central, and axial filaments were not seen.

The single specimen that I found looked much like a Suctorian of the genus _Sphaerophrya_, but the absence of a firm cuticle and the presence of food-taking pseudopodia with granule-streaming makes it a very questionable Suctorian, and 1 place it here until further study throws more light upon it.

Diameter of body 40; length of pseudopodia 120 to 140.

[Ill.u.s.tration: Fig. 5.--_Actinophrys sol_.]

Genus HETEROPHRYS Archer.

The body is globular with but slight differentiation into ectoplasm and endoplasm; one nucleus in the latter; contractile vacuoles one or many; pseudopodia on all sides, thin, and with peripheral granule-streaming; surrounded by a globular, rather thick coat of jelly, which is hyaline inside and granular on the periphery. Fresh and salt water.

Heterophrys myriapoda Archer. Fig. 6.

Synonym: _H. marina_ Hert. & Less. '74.

Diameter 25 to 80; pseudopodia twice as long as the body diameter; the plasm often contains chlorophyll bodies (Zoochlorella). The granular part of the gelatinous layer is thick (up to 10). The spine-like processes are very thin and short. (Schaudinn '95.) The marine form found at Woods Hole probably belongs to this species, as described by Schaudinn. The short pseudopodia which give to the periphery a fringed appearance are quite regularly placed in connection with the pseudopodia. The latter are not so long as twice the body diameter, the longest being not more than equal to the diameter of the sphere. The body inside of the gelatinous covering is thickly coated with bright yellow cells similar to those on Radiolaria. The animal moves slowly along with a rolling motion similar to that described by Penard '90, in the case of _Acanthocystis_. Diameter of entire globe 35; of the body without the jelly 18. The extremely fine granular pseudopodia are 8 to 35 long. Common among algae.

This form was probably meant by Peck '95, when be figured "a heliozoon."

[Ill.u.s.tration: Fig. 6.--_Heterophrys myriapoda_.]

KEY TO ORDERS OF FLAGELLIDIA.

Small, body usually amoeboid; 1 or more Order MONADIDA.

flagella; no mouth

Small; plasmic collar around the Order CHOANOFLAGELLIDA.

flagellum

With 2 or more flagella; one trails Order HETEROMASTIGIDA.

behind

With 3 or more flagella, none of which Order POLYMASTIGIDA.

trails

Large; firm body wall; 1 or 2 flagella; Order EUGLENIDA.

mouth or pharynx, or both

Medium size; with chlorophyll, Order PHYTOFLAGELLIDA.

no mouth, usually colonial

Small; silicious skeleton; parasitic Order SILICOFLAGELLIDA.

on Radiolaria or free (One genus, _Distepha.n.u.s_ Stohr)

KEY TO THE FAMILIES OF MONADIDA.

No mouth; 1 or 2 flagella: amoeboid Family _Rhizomastigidae_ with lobose or ray-like pseudopodia

Mouth at base of single flagellum; Family _Cercomonadidae_ plastic; no pseudopodia

One flagellum; inclosed in gelatinous Family _Codonoecidae_ or membranous cups

One flagellum; tentacle like process Family _Bikoecidae_ at base of flagellum; inclosed in cup

One main flagellum and 1 or 2 Family _Heteromonadidae_ accessory flagella

KEY TO MARINE GENERA OF MONADIDA.*

Family _Rhizomastigidae_:

1. Flagellum repeatedly thrown off Genus *_Mastigamoeba_ and rea.s.sumed in part