Page:Scientific results HMS Challenger vol 18 part 1.djvu/46

xxvi "A. The Ellipsoidal Central Capsule, with one axis elongated, so that it becomes the vertical main axis of the body.

a. Among the, Actiprunum (p. 14), Colloprunum (p. 25, Pl. 3, fig. 9), most (p. 288).

b. Among the, many Amphilonchida (p. 782, Pl. 132, figs. 2, 6), and Belonaspida (p. 861).

c. Among the, many (p. 905, Pl. 91, figs. 5, 9),  (p. 937, Pl. 81, fig. 16), Monocyrtida (Pl. 51, fig. 3), &c.

B. The Cylindrical Central Capsule, with considerable elongation of the vertical main axis, which is several times as long as the horizontal transverse axis.

a. Amongst the, Collophidium (p. 26, Pl. 3, figs. 1-3) and many  (Spongurus, &c.).

b. Among the, some Amphilonchida.

C. The Discoidal, Spheroidal, or Lenticular Central Capsule, with one axis shorter than the others, which becomes the vertical main axis.

a. Among the, Actidiscus (p. 15), Collodiscus (p. 27), and the large group (p. 408).

b. Among the, many Quadrilonchida (p. 768, Pl. 131), and most Hexalaspida (p. 874).

c. Among the, certain and.

d. Among the great legion the spheroidal central capsule is almost always more or less flattened in the direction of the main axis (p. 1525, Pls. 101-128).

D. The Lentelliptical Central Capsule (or triaxial ellipsoid), with three unequal but isopolar axes at right angles to each other, the sections in all three dimensions of space being ellipses.

a. Among the, Actilarcus and the large group (p. 604).

b. Among the, certain Amphilonchida and Belonaspida.

E. The Polymorphic, Amœboid or Irregular Central Capsule.

a. Among the, Collodastrum (p. 28, Pl. 3, figs. 4, 5), and some."

55. The Exometamorphic Forms of the Central Capsule.—The secondary forms of the central capsule, which are brought about by external causes, chiefly dependent on the formation of the skeleton, are very various and in many cases devoid of special interest; in other instances, on the contrary, they are of great importance, because of the clear relation of cause and effect which can be traced between the development of the skeleton and of the capsule. The most important phenomena to be recorded in this connection are as follows:—