ies of a genus which, from its simple, unwound shell, would be
immediately taken for a _Patella_; the creature, however, closely
resembles the _Fissurella_, with the difference that only one gill is
visible in the fissure over the neck. It is remarkable, that on the
whole north-west coast of America down to California, no _Patella_, only
animals of the genus _Acmaea_, were to be met with. Of the _Chiton_
genus, six species were observed; in one, the side skin covers the edges
of the shell so far as to leave only a narrow strip of it visible down
the back; in others, the shell is entirely concealed under the external
skin. It is worthy of remark, that these latter, as well as one
similarly formed, found in California, attain the considerable length of
eight inches. A third kind, to be reckoned among this subdivision,
Pallas obtained from the Kurile Islands, and has described it as _Chiton
amiculatus_.

Among the Acephala are to be named a large _Cardium_, also found on the
Californian coast; _Modiolus_, two species; _Mytilus_; _Mya_, two
species; and _Teredo palmulatus_: the latter, which is brought here by
the ships, is very mischievous in the harbour, and attains to the length
of two feet. In this species are comprehended three _Ascidiae_, of
different forms; one _Anomia_, one _Terebratula_ attached to a _Fusus_,
two _Lepas_, and a _Balanus_. Six _Holothuria_, belonging to three
different species, were observed: a large _Thalassema_ gave us a
long-wished for opportunity of observing, that this species belongs to
the Holothuria, and not to the Annulides. Eight species of star-fish are
found here, partly on the rocks, and partly at the bottom of the sea:
among them, four are furnished with five _radii_, and the rest with six,
ten, eleven, and eighteen: the latter sort, which is the largest, lives
at the bottom of the sea, and the number of its _radii_ varies from
eighteen to twenty-one. Only one _Ophiura_ was seen. Several kinds of
very large _Actinia_ inhabit the rocks: all that we examined belonged to
the species which is externally provided with rows of teats. A _Velella_
also was caught in the open bay: this is the first which has been
observed in so high a latitude.

Of _Zoophytes_, some presented themselves of the genera _Antipathes_,
_Millepora_; _Cellaria_, _Flustra_ two species, _Melobesia_, _Retepora_,
_Acamarchis_, _Lafoea_, _Aglaophenia_, _Dynamena_ fives species,
_Clytia_ four species, and _Folliculina_, tw