HESIONIDAE (ANNELIDA, POLICHAETA) FROM JAPAN. I. by Hiro ...

64 Kuroshio Biosphere : BULL. BIOL. INST. KUROSHIO Vol. 1, 2004
latero-ventrally to lateral antennae (Fig. 14, B), and as long as the latter. Articulation of
palpi at the site of proximal 1/3 or a little more proximal. Two pairs of circular eyes
located latero-caudad, but shifted dorsally comparing with other species of the genus.
Anterior pair of eyes larger than posterior pair (Fig. 14, B). Each of anterior three
segments with two pairs of tentacular cirri. Dorsal tentacular cirri on segments I-III almost
in same length. Ventral tentacular cirri shorter than their dorsal partners. Pygidium lost anal
cirri.
Parapodium biramous. Each parapodium with a dorsal cirrus, a neuropodial cone, and
a ventral cirrus (Fig. 14, C). Notopodial part of the median parapodium with a cirrophore
and a cirrostyle. Notopodial cirrophore cylindrical with a considerable length, with a
conspicuous constriction at distal 1/3 of whole length. The diameter of notopodial
cirrophore somewhat reduced in distal part from the constriction. Notopodial cirrophores
rather well ciliated (Fig. 14, D). Notocirrus with faint articulation on its distal half (Fig.
14, C). Each notopodium of median part of the body with a couple of acicula, and the tip
of one aciculum reached to ventral side of the constriction (Fig. 14, D-E). Several
posterior notopodia with a single aciculum in each of their cirrophore, and in the anterior
part of the body from setigers I-II, each notopodium with 4 or 5 acicula. A small tuft of 1
-7 notoseta beside the aciculum tip. Each median neuropodium with a single or two acicula
(Fig. 14, C-D). Neuropodial presetal lobe formed a short cylindrical projection with round
tip (Fig. 14, C-D). Neuropodial postsetal lobe formed wide triangular edge (Fig. 14, D).
With each 16-17 setae in supla-acicular and sub-acicular position in median neuropodia.
Neurocirri long subulate or almost cylindrical, inserted far ventral from the ventro-lateral
corner (Fig. 14, D).
Notosetae forked form (Fig. 14, E), and neurosetae with normal form of the genus
(Fig. 14, F-J). Tip of shaft of compound setae simple pointed, but with a shallow
excavation near the tip (Fig. 14, K). Sub-acicular neurosetae show the species belongs to
short setae group. The supla-acicular one or two setae of inferior position in developing
stage with a long hood (Fig. 14, H).
REMARKS.
O. pugettensis is characterized by notopodial cirrophores of medium length, with a
constriction on cirrophore, situated rather proximally, and the diameter reduced on distal
part from the constriction. The form of presetal lobe are also specific characters of the
species.
Podarke furcata Hartmann-Schröder may be the same species. The separate or
diffused condition of Segments I and II should be depend on the protruded condition of
proboscis. The form of distal part of neuropodial presetal lobe sometimes with round head
or sometimes with rather dully pointed apex. Membranaceous hood by Hartmann-Schröder
(1962, Taf. 5, Abb. 29a) are same as my specimens (Fig. 14, H).
It is impossible that Japanese record by Hessle (1925) is surely the species or not,
for the incomplete or rather almost no description was given. O. pugettensis collected in the
sheltered muddy areas in the case of west coast of U.S. (Hartman, 1968) and my
specimens.
Following is the key to the Japanese species of the genus Ophiodromus.