J. D. Dana on Zoophytes. 13 
48. Both lateral and terminal budding may go on continuously, 
in the same manner as buds proceed from the creeping shoot of 
a plant. Avshoot or process continues elongating uninterrupt- 
edly, and at intervals gives out a young polyp; and in the same 
manner the margin of a growing folium may be constantly widen- 
ing and giving out young polyps as it widens. This process is 
called by Ehrenberg, gemmation by stolons. Thus, while in 
some zoophytes the buds are produced only after intervals of 
time, the young approaching its adult size before budding, in 
other cases the process of budding and growth proceed together, 
In the one case the growth of the young absorbs the nutriment 
for the time being, and in the other, the nutriment goes at the 
same time both to promote growth and gemmation. 
49. Modes of Growth.—1. The polyps of a compound group 
may be united at base only, and each may grow out as a separate 
branch, as in figure 32. 2. They may be Fig. 32. 
calicles. Thus we explain many of the peculiarities of corals. 
When each polyp forms a separate branch, as 1n figure 32, the 
cophyte may be said to be segregate in growth; but when they 
are laterally coalesced as in the massive Astreas and the re- 
omes a separate branch. eae 
50. 2. Polyps differ also essentially in the process of growth. 
1. Some polyps on reaching the adult size cease farther growth. 
2. Others continue endlessly their growth above, and after a 
h bel that life and 
* From axgoy top; and yevvaw, J increase, 
