PROTOZOA OR SIMPLEST ANIMALS. 



11 



coloured with crimson, blue and yellow tints, and have been well High Wall 

 termed " gems of the ocean." Their skeletons assume an endless ^^^® , 

 variety of beautiful and curious shapes, such as spiny latticed GaUery? 

 spheres, rings, beehives, &c. The Radiolaria, of which about 

 4,000 species have been described, are primarily classified according 

 to the structure of the central capsule, the shape of the skeleton 

 tending to conform, more or less, to the shape of the latter. 

 Professor Haeckel divides the group into four Orders : — 



Fig. 8.' 



Haliomma wyv!llei. MagniBed 200 diameters. (After Wyville Thomson.) 



I. Spumellaria (Fig. 8), and see Plate VII. and Models 9-12 

 in the Case, with spherical central capsule uniformly perforated by 

 pores. Here the skeleton is typically formed of a latticed sphere or 

 of several concentric latticed spheres united by radial beams which 

 do not penetrate the central capsule, and with radiate spines. 



' From " The Voyage of the CJiallenger— Atlantic" 



