expanded, often becoming broadly wedge-shaped. Sometimes the frond 
remains nearly linear throughout. The surface of barren specimens is 
smooth, but fertile individuals are more or less densely sprinkled over with 
filiform processes, which are sometimes prolonged to two or three lines; 
but more commonly are shorter, swelling in their upper part into an oval or 
globose tubercle. These processes, though sometimes borne on both 
surfaces, are generally most abundant on the channelled side. The tubercles 
contain, within a thick wall composed of radiant fibres, an elliptical mass 
of densely packed, minute spores. I have not seen ¢etraspores. The strue- 
ture of the frond is dense. Its substance tough, between cartilaginous and 
leathery, very rigid when dry, and not adhering to paper. The colour a 
very dark, brownish purple, becoming brighter and more pinky after long 
steeping in fresh water. 
Rw 
A common species on all parts of our shores, and dispersed 
throughout the Atlantic basin. Notwithstanding its well-marked 
characters, it has been confounded at one time with Fucus cana- 
liculatus: an error hardly to be anticipated, when the substance 
and colour are so exceedingly unlike; and afterwards with 
Chondrus crispus, to which there is a closer resemblance, though 
the channelled frond, rough with papille, clearly distinguish the 
present plant to the naked eye; while a difference in structure 
has latterly caused them to be placed in distinct genera. Gzgar- 
tina mamillosa was first accurately determined and described by 
Goodenough and Woodward, in 1797. Its claims to specific 
rank have been generally admitted since that time, except hy 
Lamouroux, who considers it a variety of C. crispus. Some 
states of the latter it, deed, closely resembles, but is always 
distinguished by the channelled frond. Its officinal properties are 
similar to those of the Chondrus, and it is, on some shores, indis- 
criminately collected with that species, and dried as ‘‘ Carrigeen.” 
I regret that our plate has been printed in rather too pale an 
ink. 
Fig. 1. CHonDRUS MAMILLOSUS :—of the natural size. 2. Apex of a fertile 
frond :—slightly magnified. 3. Vertical section of a tubercle. 4. Spores 
from the same. 5. Vertical semisection of the frond. 6. Transverse section 
of the same :—highly magnified. 
