Inter-tidal Ecology at Narrow Neck Reef — Dellow 
361 
most of the day and has a southwesterly as- 
pect. Codium adhaerens flourishes here while 
Hormosira is absent. Telescoping of belts 
with increasing angle of slope is evident. 
Traverse C (Figs. 1, 5): Crab Island, across 
the shorter axis, at right angles to Traverse 
B; length 70 feet; bearing 46° 40'. 
Traverse C shows Crab Island in profile 
from the shore to the seaward face of the 
island. The change in nature and in specific 
composition of communities with change in 
level is very similar to that in Traverse B. 
Enteromorpha procera f. minuta and Elmi- 
ntus plicatus are poorly developed on Crab 
Island. It will be observed that the encrust- 
ing coralline belt descends lower than usual 
to seaward. Corallina and Hormosira are 
growing just below the 8-foot level, 4 feet 
above their normal upper limit, under pool 
conditions. 
Traverse D (Figs. 6a, b) : St. Leonard’s 
Point; length 269 feet; bearing 45°. 
Traverse D, the longest, runs in a direct 
line from high to low water. It is not shown 
on the map of the reef because the shape 
of the area as a whole is too awkward to 
allow the inclusion of St. Leonard’s Point on 
a map of that scale. 
The strata of the cliffs above the point are 
not tilted as they are at the Headland. The 
dip and strike of the ledges below form a 
correspondingly regular sequence from the 
cliff base to the seaward end of the point. 
Much of the intervening rock is flat and is 
covered with thick deposits of mud. The 
water about the point is always turbid with 
much suspended matter from the sewage out- 
flow. The general zonation, however, is re- 
markably similar to that obtaining at Narrow 
Neck. 
Melaraphe oliveri and Calothrix scopulo- 
rum are widespread between M.H.W.S. and 
E.H.W.S. Beneath the overhanging ledge 
36 feet from the start of the traverse, Ralf- 
TRAVERSE C - ACROSS CRAB ISLAND 
AT RICHT. ANGLES TO TRAVERSE B 
Vertical Scale 
Horizontal 
UHL 1 CHAMAESIPHO COLUMNA 
E HE) ELMINIUS MODESTUS 
EE3 ELMINIUS PLICATUS 
EsE SAXOSTREA GLOMERATA 
^3 ENTEROMORPHA ACANTHOPHORA* 
B3 CELIDIUM CAUL ACAN THE UM 
EZZ1 HORMOSIRA BANKSII F GRACILIS 
[HU CORALLINA OFFICINALIS 
103 ENCRUSTING CORALLINES 
Fig. 3. Traverse C. ( * Found to be Enteromorpha procera f. minuta .) 
