_Halosydna latior_ sp. nov.
A species proportionately broader over all than the usual forms of the
common _H. insignis_, _californica_, and _pulchra_. It is characterized
by elytra not only closely imbricated along each side but also broadly
overlapping in the middle line throughout the length. The elytra in
general are unusually elongate in an oblique direction, the long axis
running from the outer end cephalomesad; the outline subelliptic, the
caudomesal edge broadly convex, the opposite one a little incurved at
middle. The entire surface of elytra subdensely covered with very small
rounded brown nodules or tubercles; within the middle region, just
behind the edge of the preceding overlapping elytron, a number of much
larger paler tubercles which in the type are present on all excepting
the last pair. Elytra extending to outer ends of parapodia. Eighteen
pairs of elytra present. Prostomium subangularly bulging on each side,
the anterior eye at the angle, the posterior eye removed far caudad,
by about half the greatest width of the prostomium. Paired anterior
prolongations of the prostomium very long, as long as the median length
of the prostomium back to level of posterior eyes, distally clavate.
Median ceratophore much stouter than the lateral prolongations and
exceeding them by more than a third in length. Median tentacle long,
nearly attaining end of palpi; slender, narrowing distad, only slightly
thickened subapically, with the usual slender tip which is of moderate
length. Lateral tentacles much shorter, their tips reaching only to
near middle of light region between proximal black region and subapical
black ring of median tentacle. Tentacular cirri resembling median
tentacle in form, being narrowed distad with subapical enlargement
slight; one or two fine setae emerging from a small nodule at distal
end of parapodium proximad of tentacular cirrus. The notocirri in
general have the same characteristic form as the tentacular cirri,
narrowing continuously distad with the subapical enlargement slight.
First neurocirrus very elongate, surpassing the parapodium. The other
neurocirri slenderly cylindroconical, narrowed into a slender tip and
a little narrowed proximally; attached well toward base of parapodium
the end of which they fail much of attaining. A characteristic feature
is the elongate form of the nephridial papillæ, these in the type
as preserved being mostly near three times as long as thick at the
middle. Neuropodial setae dark amber colored, numerous, arranged in two
continuous regions, a narrow dorsal one and a much broader ventral one
in the latter of which the setae form four distinct longitudinal series
with five or six setae in each series. Notopodials moderate in number,
the dorsal ones short, the most ventral long, attaining the end of the
neuropodium. The elytra are greyish with dusky or brownish mottlings.
Notocirri with dark annulations as usual.
Length, 42 mm.; width to end of setae, 14 mm.; to end of parapodia,
10.8 mm.; exclusive of parapodia, 7 mm.
Taken on Laguna Beach at Mussel Point (Hamilton coll.).
Type--M. C. Z. 2, 138.
_Halosydna tuberculifer_ sp. nov.
Among other forms known from the California coast characterized
especially by the strong tuberculation of all the elytra. The tubercles
are mostly large and conical though some are rounded and are confined
chiefly to the mesocaudal half and median region of each elytron, a
series of large ones ordinarily present along the caudal and caudomesal
margin; in the first two or three pairs of elytra the tubercles
of the median region especially large, the tubercles on the first
pair occurring on the anterior part as well; ectal margin of elytra
strongly fringed or ciliate. Elytra in general subcircular but with
margin of ectocephalic side flattened or in part a little incurved.
Elytra in contact or nearly so at median line but not there at all
overlapping. Pairs of elytra eighteen, these being present on somites
II, IV, V, VII, IX and so on alternate ones to XXV and then on XXVI,
XXVIII, XXX, XXXI, and XXXIII. The last three setigerous somites bear
notocirri. Anterior pair of eyes near middle of length of prostomium
proper, larger than posterior pair which are a little closer together
and are well removed from the others. Lateral prolongations of the
prostomium in front which bear the lateral tentacles only a little
shorter than the median ceratophore though much more slender. Median
tentacle shorter than the palpi, moderately enlarged and strongly
rounded subapically and with the usual slender tip or filament which
is comparatively short. The lateral tentacles of similar form but
much shorter and more slender. Neurocirri of first normal segment
large, resembling a notocirrus. The other neurocirri much shorter,
subconical, constricted at base and prolonged into a slender but short
tip; attached near base of neuropodium in each case. Anal cirri similar
to notocirri but much longer and stouter. Neuropodial setae of usual
general form, amber colored with dark tip, arranged mostly in two or
three, usually uneven, subvertical series. The notopodial setae fine,
numerous, the longer ones not falling much short of or reaching the
ends of the neuropodials. The nephridial papillæ occupy the ordinary
position; they are small and unusually short. The color of the elytra
uniform greyish brown. Antennæ, tentacular cirri and notocirri banded
at base and distally with black.
Length, 23 mm.; width exclusive of parapodia, 3 mm. A little narrowed
cephalad, somewhat more so caudal.