204 CUBAN SEAWEEDS. 
float in the endochrome and fill a good part of the cell. These 
threads are merely prolongations of the external cell-wall, and 
are not newly formed cells, as they contain no endochrome. 
Harvey has compared the Caulerpz to loose sponges surrounded 
by a membranous sac. 
The specific distinction depends on the outline of the frond. 
Most of them resemble Lycopods or true mosses. In all, there 
is something which looks like the subterranean stem of a Lycopo- 
dium, from which fibrils resembling roots are given off. These 
have not the functions of roots, but only serve to fix the plant, and 
stems, the Caulerp are able to 
in consequence of these trailing f 
almost no other alga will grow. 
flourish on a sandy shore where 
Fig. 53. 
Fig. 52. 
Halimeda tridens, 300 diam. 
Trdat flabellata. 1-2 natural size. 
From these underground stems, or surculi, grow the fronds propel 
consisting of a single cell, as we have described. In C. prolifer 
the frond is simply flat and leaf-like. In C. plumaris it 1s finely 
pinnate, resembling little feathers. In C. Mexicana (Fig. 50, nat 
ural size) we have some resemblance to a Jungermannia ; while 
in C. Lycopodium and ericifolia (Fig. 51, 3 natural size) we have 
forms presenting a striking similarity to Lycopodium clavatum and 
dendroideum. In fact in the dried state many would mistake them 
for faded Lycopodia. The Caulerpx grow near the shore in great 
patches as densely clustered as the mosses on shore. They form 
the lawns of the ocean, but far excel, in brilliancy of color and 
delicacy of form, the lawns which the most skilful gardener Cat 
produce. They are also said to form the chief food of the gree 
turtle of our markets. 
