206 THREE CRUISES OF THE “BLAKE.” 
concerned, they naturally procure their most abundant supply 
of food within a comparatively short distance from land, where 
All the detritus brought down by rivers, or formed by the action 
Fig. 120. — Zoea of Carcinus. Fig. 130. — Panopus Embryo. 
8 i 1 MO : 
Weatly magnified. Greatly magnified. 
Fig. 131. — Zoea of Porcellana. 5. 
B 1 
of the sea on the coast line, settles on the bottom around the 
slope of the continental areas. The larger materials are left 
close to the shores, and with increasing distance the detrital mat- 
ter becomes smaller, till finally reduced to an impalpable ma- 
terial or solids in solution it finds its way to the most distant 
parts of the continental slopes, or is carried still farther by 
oceanic currents skirting the shores. As I have shown in the 
chapter on the Florida Reefs, the distribution of the deep-sea 
fauna is really a question of food; and we may expect to find it 
most abundant upon the continental shelf,—along the lines to 
which the greatest amount of detritus is carried by the incessant 
action of the varied winds, tides, and currents to which the 
sea-shore is exposed. 
