46 BOTANICAL GAZETTE [JANUARY 
with geological hammers for breaking off fragments of coral; and with sundry 
haversacks, bottles, wide-mouth vials, etc. With our water boxes as guides 
we wandered for three delightful hours over the ledges, knolls, and sandy 
pockets of the reef; collecting, exploring, and rejoicing in the luxuriant abun- 
dance of marine life of every form and color. Branches of living coral; many 
kinds of curiously shaped shells; bright spotted crabs and crustaceans of vari- 
ous sizes; spiny sea-urchins; spidery-armed brittle-stars; exquisitely beautiful 
hydroid colonies; purple and black sea-cucumbers; delicate marine algae of 
many genera, reds, browns, olives, and greens of varying tints, a kaleidoscopic 
succession of queer marine organisms. 
ECOLOGICAL ZONES ON REEF 
The typical fringing reef exhibits 5 distinct zones or areas of 
plant and animal life. This zonation is best developed on the reefs 
with wide lagoons and a well defined outer margin or rim. 
1. Beach or inshore waters —The shallow inshore waters, varying © 
in depth from 6 to 36 inches, sustain a number of the quiet water 
forms, such as Enteromorpha spp., Hypnea nidifica, Gracilaria 
coronopifolia, Chaetomorpha antennina, Ulva spp., Chondria spp., 
Liagora decussata, etc. The bottom is of coral sand or mud, more 
or less contaminated with volcanic wash from the mountains. 
The nature of the bottom depends upon the proximity of streams 
and the strength of the surf. In many places (Kai-lua, Mo-kapu, 
Mana) the bottom is pure white coral sand, with practically no mud 
or rock. In other districts (Kalihi, Nu’u-anu, Kane-ohe) there 
are large “mud flats” exposed at low tide, and the bottom here is 
very muddy and rocky, with little sand. Every gradation may 
be found between these two extremes. At the mouths of streams, 
and at other places along the coasts where fresh water springs exist 
below the tide level, the inshore water is sufficiently brackish to 
prohibit the development of the strictly marine species. 
2. Partially submerged rocks.—In some places the beach and 
shallow waters are devoid of rock masses, but as a general condition 
one finds partially submerged rocks scattered all along the coasts. 
These may be either close inshore, in the form of ledges or little 
cliffs, or may lie at varying distances from the shore. In any case 
they distinctly indicate, by their horizontal bandings of algal and 
hydroid life, the ranges of high and low tide. These rock masses 
