The Matrix, placed between the calymma and central capsule, is, in the majority of the Spumellaria, a rather thick layer of granular exoplasm.

The Pseudopodia arising from it are very numerous, equally disposed over the whole surface, and are in general rather fluid, exhibiting a considerable tendency to ramify, anastomose, and form networks. The movement of granules is commonly lively. In the Polycyttaria all capsules of one colony or "cœnobium" are connected by the dense variable network of anastomosing pseudopodia.

Synopsis of the Orders and Suborders of Spumellaria.

I. COLLODARIA.

Skeleton wanting or quite imperfect, not latticed.

Skeleton entirely wanting,1. Colloidea.
Skeleton represented by numerous scattered spicules,2. Beloidea.

II. SPHÆRELLARIA.

Skeleton a perfect shell of lattice work, or spongy and resembling wicker-work.

Lattice-shell spherical or composed of concentric spheres,3. Sphæroidea.
Lattice-shell ellipsoidal or prolonged in one axis,4. Prunoidea.
Lattice-shell discoidal or shortened in one axis,5. Discoidea.
Lattice-shell lentelliptical, with different extent of growth in three axes,6. Larcoidea.
I. COLLODARIA. Skeleton wanting or quite imperfect, not latticed.
Skeleton entirely wanting,
1. Colloidea.
Skeleton represented by numerous scattered spicules,
2. Beloidea.
II. SPHÆRELLARIA. Skeleton a perfect shell of lattice work, or spongy and resembling wicker-work.
Lattice-shell spherical or composed of concentric spheres,
3. Sphæroidea.
Lattice-shell ellipsoidal or prolonged in one axis,
4. Prunoidea.
Lattice-shell discoidal or shortened in one axis,
5. Discoidea.
Lattice-shell lentelliptical, with different extent of growth in three axes,
6. Larcoidea.

Order I. COLLODARIA, Haeckel, 1881.

Collodaria, Haeckel, Prodromus, 1881, p. 469.

Collida et Sphærozoida, Haeckel, 1862, Monogr. d. Radiol., pp. 246, 522.

Definition.—Spumellaria without latticed shell.