at maturity, an oval, transversely striate, dark green mass, which is even- 
tually discharged through a terminal pore. 
DO 
At plate XXXYV, I figured two of the more minute species of 
Codium ;* 1 here present one which is of larger size, more gene- 
rally known, and the most widely dispersed of the genus. It 
occurs throughout the Pacific Ocean from the shores of Arctic 
America and Asia, to the southern extremity of America; and is 
equally dispersed throughout the Atlantic. In general features, 
specimens from most countries agree, but there are slight points 
of difference, on which authors have founded species, which I can- 
not but regard as mere varieties of a common type. Such is the 
C. elongatum of Agardh, an admirable figure of which is given in 
the splendid ‘History of Algiers,’ now publishing under the 
auspices of the French Government. This form, which accom- 
panies the common C. tomentosum on the West coast of Ireland, 
is chiefly remarkable for a great dilatation of the frond imme- 
diately under the forking of the branches. This enlargement 
certainly gives the specimens a distinct look, but traces of it may 
be found in various degrees of development, inseparably con- 
necting the most dissimilar looking individuals of C. e/ongatum, 
with the common dichotomous, filiform C. tomentosum. Were 
C. elongatum admitted as a species, several other forms might be 
enobled on grounds as valid. There is, for instance, a common 
state of this plant, which is very irregularly divided, having the 
branches set with numerous lateral branchlets half an inch to 
an inch long, which is as abnormal as C. elongatum. 
Codium tomentosum has to the naked eye quite the appearance, 
though not the substance or structure, of a sponge; and, indeéd 
very closely resembles in form and colour the Spongia hspida, 
Mont., offering a beautiful instance of azalogy between organisms, 
whose afinity is widely separated. 
* To the habitats given under Pl. XXXV. for C. adherens add Rathlin Island), 
Antrim, Mr. D. Moore, and Tory Island, Mr. G. Hyndman. Mr. Moore’s spe- 
cimens were gathered in 1834, and to him, therefore, the credit. of being the 
discoverer of this plant in Ireland belongs. 
Fig. 1. Coptum tomENntosum:—of the natural size. 2%. Filaments of the 
periphery, with fruit :—Aighly magnified. 
