491 
My reason for regarding this as an independent variety, instead 
of including it under var. micrococca , which Hauck, e. g. (»Die 
Meeresalgen Deutschlands und Oesterreich«, p. 432) points out as 
perhaps the most correct course, is that I have found quite typical 
specimens of it, although not in any great number. This variety 
as already mentioned under var. micrococca is otherwise intimately 
connected with the latter through intermediate forms. 
var. compressa (L.) Rosenv. 1. c. p. 958; Ulva enteromorpha 
compressa Le Jolis, Liste, p. 44; Scytosiphon compressus Lyngbye, 
Hydrophyt., p. 64, ex parte. 
Some of the specimens referred to this variety are almost 
branchless, though branching or prolific specimens have also been 
found. Some of these are somewhat similar to f. complanata. 
Others, more richly ramified, closely resembled in habit E. clathrata , 
from which species they may generally be distinguished, as pointed 
out, e. g. by Re in bold, by the fact that the cells of E. clathrata 
are arranged in rows; it must, however, be borne in mind, that 
this character cannot always be applied, as I have found specimens 
in which the cells in the same individual were sometimes in rows, 
and sometimes without any arrangement whatever, in fact every 
degree of development exist in the arrangement of the cells. A 
transverse section of the typically developed plant shows the inner 
wall to be thin while through others may be traced a quite gradual 
transition to the more or less thickened inner wall of E. intestinatis. 
Of var. compressa , I have found a forma trabecutata , which 
exactly resembles that which Rosenvinge (1. c. p. 961) has des¬ 
cribed under E. prolifer a. The specimens were found in tide-pools 
near high-water mark on the west coast of Stromo near Velbestad, 
and they could be seen by the naked eye, as the plant when alive 
almost resembled a Chaetomorpha. As pointed out by Rosen- 
vinge, complete partition-walls were not to be found here either, 
but merely plates or trabeculae more or less irregularly extended 
in transverse and oblique directions. The thickness of the trabe¬ 
culae is very slight, and, as stated by Rosen vinge, they turn 
yellow when stained by chlor-zinc-iodine. I think that a specimen in 
Lyngbye’s Herbarium, called by him Scytosiphon compressus, 
may be referred to this variety; another from Naes, 0stero, has a 
rather thick inner wall, and must therefore be regarded as belonging 
to var. genuina. 
var . prolifera (O. F. Muller); Enteromorpha prolifera (O. F. Muller) 
