CORAL-MAKING ACTINOID POLYPS. 59 
take place in the ramose corals, and so make flat branches, 
each with a long sinuous line of polyp mouths at top. In 
all such species the tentacles stand in a line either side of 
the line of mouths as represented in figure 3 on Plate IV., 
between pages 54 and 55. 
By the simple methods here explained all of the various 
forms of Actinoid zodphytes have been produced ; and, equally 
so, those of the Aleyonoids described beyond. The tree, shrub, 
clusters of coral leaves, hemispheres, and coral net-work re- 
quire for the explanation of their origin only the few princi- 
ples which have been mentioned. The germ-polyp, growing 
upward and more or less outward, and budding as it grows, 
makes thus the rismg stem —that of the Madrepore or Den- 
drophyllia, with its summit polyp (figures p. 50, 51), or that of 
the Porites, with its terminal budding clusters (p. 53); or the 
rising, massive dome of the Astrea and Meeandrina (pp. 57, 
65), in case budding is symmetrical in all directions; or, if 
growth in the germ-polyp is upward exclusively, it forms a ris- 
ing stem bearing at top the single polyp that originated it, or 
crowded clusters of such stems branching variously and having 
each branch surmounted with its one polyp (figure p. 54); or, 
if there is lateral growth and but little of upward, it produces 
leaf-like forms and graceful groups or clusters of leaves, vases, 
and other shapes; or, if the germ-polyp is capable of lateral 
growth alone, the results are simple lines of polyps creep- 
ing over the supporting rock, like the creeping stolons of 
a plant, or else encrusting plates, spreading outward like a 
lichen. 
In the descriptions of corals the following terms have the 
significations annexed. Those already mentioned are here 
repeated to bring them all together. 
