56 MARINE ALG 
E. lanceolata. Formerly called Ulva Linza. Frond narrow, ribbon- 
like, six to twelve inches long, one inch to two inches wide; blunt or 
pointed at apex, tapering at base; attached by a disk; edges much 
ruffled; bright green, soft, thin. 
Genus Monostroma 
This genus resembles Ulva, but is more delicate since it has 
but one layer of cells, as its name implies. The frond is usually 
sae-like at first, then breaks apart, leaving a thin, semi-trans- 
parent membrane of no definite shape. 
GROUP SIPHONEZ 
The distinct and peculiar character of this group is that in each 
individual the whole plant consists of but one cell. There are 
many genera, some of which are plants of elaborate form and 
considerable size, but always the one cell expands and branches 
without dividing the elongated cavity with septa, or plates of 
division. In Caulerpa the stability of the plant is secured by 
numerous fibrils which emanate from the interior of the cell, 
forming a spongy network of interlacing filaments. In other 
orders the branches gain support from inecrustation, from inter- 
lacing, and from cohering on the edges. 
ORDER VALONIACEZ: 
The algee of this order are found only in tropical or subtropical 
waters. Their holdfasts resemble fibrous roots and penetrate the 
sand or coral on which they grow. 
Genus Chamedoris 
Cc. annulata. When young this alga consists of an annulated tube 
formed of a single cell. The annular constrictions occur at short inter- 
vals, giving it the appearance of being jointed. It grows to the height 
of two to three inches, when it ceases to lengthen and produces a dense 
mass of filaments, forming a head or spherical tuft one inch or more in 
diameter. It is bright grass-green in color, rather rigid and tough, and 
when mature is thinly coated with carbonate of lime. The holdfast is a 
tuft of fibers. The species is found at Key West and is a native of the 
‘West Indies. 
