IV. 
CHORD ARIACEiE. — Mesogloia. 
125 
curved or flexuous. In some specimens these forked branches are quite naked ; in 
others furnished with patent simple or forked ramuli from half an inch to an inch 
in length ; and in others beset with a multitude of such ramuli, or of more com- 
pound ones. In these last the frond becomes excessively branched, with all its 
divisions divaricated and beset with irregular branchlets. When young, the axis is 
solid, firmly cartilaginous and cellular, but with advancing age the central cells die 
out, and the stems and branches become fistular, or even somewhat inflated. Such 
specimens also lose much of their original lubricity, and may readily be mistaken 
for a different species — or even for a Stilophora , if care be not taken to observe the 
filaments of the periphery. These filaments afford a tolerably definite specific 
character in being slender, with a large terminal cell ; but in individuals of 
different ages the size of the terminal cell varies considerably. The colour is a 
greenish olive, paler than in the former species, but becomes dark brown in old 
age and in drying, in which latter state the plant adheres to paper and shrinks very 
considerably. 
Plate XI. A. Frond of Chord aria divaricata , the natural size ; fig. 2, cross 
section of a young branch; and fig. 3, the same of an older branch, both equally 
magnified ; fig. 4, a spore and two peripheric filaments, highly magnified. 
II. MESOGLOIA, Ag. 
Frond cylindrical, branched, cartilagineo-gelatinous, solid, at length partially 
hollow in the centre, coated with a pile of radiating, horizontal, branched peri- 
pheric filaments. Axis composed of longitudinal, articulated, anastomosing fila- 
ments, connected together into a network, which is laxer toward the centre ; the 
cells of the inner filaments long, those of the outer shorter. Filaments of the 
periphery rising from the outer layer of axial filaments, moniliform, composed of 
ellipsoidal cells, fasciculate, frequently dichotomous. Spores obovoid, attached to 
the base of the peripheric filaments, and concealed among them. 
Plants with the habit and much of the structure of Chordaria , but of a more 
gelatinous substance and looser texture. In this group I propose to include 
Myriocladia of J. Agardh, the structure of which does not appear to me to be 
essentially different from that of ordinary Mesogloice , while the external habit is 
so similar that even the specific diversity of the species of Myriocladia from species 
referred by Agardh to Mesogloia is variously held by different authors. Careful 
analyses of recent specimens in various stages have still to be made ; for though 
these plants can be tolerably well observed in a dried state, it is not easy in that 
state to isolate the filaments of the axis so as to show the structure perfectly. For 
