12 
GUIDE TO THE CORAL GALLERY. 
High Wall 
Case 
E. end of 
Gallery. 
Spongosphcera (Model 12) has three spheres, the outermost consisting 
of a spongy reticulum ; the fine smooth spines in this model represent 
pseudopods, but the pseudopod rays are headed in the other models. 
Spongosphcera streptacantha , which is common on the surface of 
warm-temperate and tropical seas all over the world, is about 
of an inch in diameter. 
TT. Acantharia (Fig. 9, and Model 13), with spherical porous 
Fig. 9. 1 
central capsule, with skeleton of “acanthin,” constructed of 20 
radiate spines proceeding from the centre, and always arranged in 
fours according to a definite law known as “ Muller’s Law.” The 
idea of a terrestrial globe with -its parallels helps one to realize the 
plan ; thus Haeckel calls the five fours equatorial, tropical and 
1 From “The Voyage of the Challenger. — Atlantic.” 
