by Mr. Lilly Wigg on the Norfolk shore, about the year 1790, 
and first described by Mr. Dawson Turner in a paper read before 
the Linnean Society in 1801. Since that period it has been 
detected on many different parts of the English and Irish coasts ; 
but not as yet, that I am aware of, in Scotland. 
Some doubts respecting its true affinities have been entertained 
by modern systematists, but all seem now to be agreed in referring 
it to the neighbourhood of Mesogloia; an affinity suggested by 
its first describer ; long neglected, and afterwards independently 
taken up by Mrs. Griffiths, under whose sanction I referred it in 
1836 to its present position. The structure of the greater part 
of the frond is indeed very different from that of the Glozocladee, 
the peripheric filaments which form so remarkable a featare in 
that family, bemg wholly wanting im the stem and branches ; 
but the habit and gelatinous substance are very similar, and the 
structure of the ultimate ramuli agrees very nearly with that of 
the whole frond of Mesogloia. 
In the Mediterranean it appears to be of as unfrequent occur- 
rence as on the British shores, and has only, as yet, been found 
by M. Risso. A second species of the genus, WV. Schousboer, J.Ag., 
is found on the shores of Morocco ;—it is said to have flat, many 
times pimnated fronds. 
ee EEE eee 
Fig. 1. Naccarta WieGuit :—uzatural size. 2. Part of a branch. 3. One of 
the fruiting ramuli. 4. Filaments of which this is composed, with spores 
in situ. 5. Spores removed. 6. Transverse section of the stem. 7, Lon- 
gitudinal section of the same :—all magnified. 
