262 ALGZ ANTARCTIC. 
Ramuli per totam frondem sparsi, apicem versus crebrio- 
res, erecti et erecto-patentes, subulati, 1-3 lineas longi, 
alterni vel sepius secundi, simplices vel parum divisi. 
Coccidia solitaria, globosa, spinis 4-6 magnis subulatis ar- 
mata, in apicibus ramulorum immersa, sporis numerosis- 
simis minutis repleta.  Tetrasporæ ignotæ. Color intense 
ruber, siccitate obscurior. Substantia firma, cartilagineo- 
carnosa. Charte adhæret. 
We cannot satisfactorily include this plant under any esta- 
blished genus. It belongs unquestionably to the Delesseriee, 
and will stand near Plocumium, from which it differs in the 
structure of the frond, as wellas in the fructification. The 
densely cellular axis, surrounded by large empty cellules or 
tubes, is quite unlike Plocamium. Outwardly there is a close 
resemblance between our plant and Heringia rostrata, J. Ag. 
(Gelidium ? rostratum, Griff. Fucus alatus, a, angustissimus, 
Turn.), but besides the difference in fructification, the struc- 
ture of that plant is uniformly dense, without a trace of 
large cellules or tubes, Again, our plant may be compared 
with Microcladia, to which it approaches in habit, and to a 
certain extent, the spinous coccidia may be considered ana- 
logous to the involucrated favelle of that genus ; but in 
Microcladia the axis, far from being the densest part of the 
frond, is tubular. ; ; 
27. Iridæa dichotoma, nobis; stipite brevi .cartilagineo 
mox cuneato furcato vel -pluries dichotomo sensim 1n 
frondem membranaceam ample cuneatam vel obovatam 
 desinente, segmentis frondis vel simplicissimis integris vel 
furcatis vel dichotomis, ad marginem denticulatis vel 
grosse dentatis vel lobatis vel frondes novas emittentibus, 
substantia tenui nitente lubrica demum fructibus immersis 
numerosissimis verrucosa, | 
Han. Falkland Islands. 
_ Notwithstanding the repeatedly branching, sometimes €x- 
cessively dichotomous frond and other characters above 
noticed, we are not sure whether there be any exact limits 
defineable between this form and I, micans, which, like most 
