resting alga is one of his recent acquisitions, and not the least
beautiful. As yet it must be accounted extremely rare.
Polysiphonia spinulosa belongs to the genus Hutchinsia,
constituted by A g a r d h in honour of the late excellent Miss
H u t c h i n s . He could not, however, have been aware, that
Mr R o b e r t B r o w n had previously given the same name to
a genus of the Order Crucferce. As there is no doubt attached
to the propriety of Mr B r o w n ’s genus, it is absolutely necessary
to change that of A g a r d h ; and it is only to be lamented,
that the great knowledge Miss H u t c h i n s possessed
of Marine Alga, cannot be commemorated by bestowing her
name on a group of that order. The name I have now given
to the genus, is derived from the peculiar structure which all
the species possess.
Fig. 1. Polysiphonia spinulosa, nat. size. Fig. 2. A branch magnified. Fig. S.
A portion of a main branch, with a tubercle. Fig. 4. The termination o f a
branchlet, nith the pellucid fiaments. Fig. 5. Tubercle.
L’J -