ZOOLOGY: L. R. GARY 
547 
rigidum but is commonly found in slightly less favorable conditions than 
the latter by which it is, on account of its habits of growth, easily crowded 
from the most favorable locations. 
The fourth species A. flexilae is by far the most dehcately branched 
and is also incapable of retracting its branches. It is consequently 
restricted to very quiet waters in the most protected locations on the 
reefs. 
To determine the proportion of alcyonaria in different locations on 
the Pago Pago reefs clearly marked lines were run across a number of 
the reefs fiom the shore to their outer edges. Along these lines squares 
25 feet on a side were laid off and the area occupied by alcyonaria esti- 
2i 
100 200 .00 400 500 600 
Distance in feet from shore. 
FIG. 1 FIG. 2 
Fig. 1. Showing the distribution of the alcyonaria across the Utelei reef Pago Pago 
harbor, Samoa. The figures along the ordinate represent the distance in feet from shore, 
those along the abscissa the area in square feet covered by alcyonaria on each square the 
sides of which were 25 feet in length. 
Fig. 2. Showing the distribution of three species of alcyonaria along a line the total al- 
cyonaria of which is shown in figure 1. 
Distribution as shown in the previous figure. Alcyonium glaucum, o ; 
Alcyonium confertum, 0 ; Alcyonium rigidum, + 
mated for each square. Figure 1 shows the conditions on a reef along 
the south side of a cove at Utellei village which is situated on the west 
side of Pago Pago harbor about three-quarters of a mile from its entrance. 
On account of the configuration of the shore line at this place a 
strong current sets across the reef area traversed by the outer half of this 
line, vv^hiie over the inner portion the currents are very weak. The depth 
at extreme low tide varies from 6 to 15 inches over all of this reef except 
the hthothamnuium ridge which is exposed for a width of from 50 to 
75 feet. 
Figure 2 shows the area occupied by each one of the three species- 
occurring along this line. The thickness of the rock formed from spicules 
