_Leaena videns_ sp. nov.
The prostomium extends as a convex hood or inverted scoop above the
mouth; along its posterior border is a series of long, crowded,
tentacles. The prostomial fold behind the tentacles is crossed by a
transverse band of distinct eyes, the band narrow above and widening on
each side. Mouth a crescentic slit with corners curved caudad; bordered
behind by a thick lip the anterior median edge of which is truncate.
No dorsal cirriform process on III or any other segment, all being
wholly smooth. A characteristic of the species is the large number of
setigerous segments, at least thirty-one being present (IV-XXXIII) in
the type, and possibly more. The setæ differs from those of _nuda_
in their longer fine tips and more geniculate appearance at base of
this region. The uncini are characterized by an exceptionally long
beak which, beyond its strongly curved base is straight; the sinus
narrow, the process arising near its middle, low obtuse; vertex not
comparatively high, crossed by mostly four series of denticles; body of
uncinus rather narrow, the shoulder on convex side much farther toward
the end than, e.g., in _nuda_ and well below level of bottom of sinus.
The type is incomplete, only near thirty-eight segments being present.
The color is noted as pinkish in life. At present it is fulvous in the
type.
Length of incomplete specimen not in excess of 12 mm.; greatest width,
.8 mm.
Type--M. C. Z. 2, 167.
_Pista fratrella_ sp. nov.
This form seems to be close to _P. alata_ Moore. The type, which is
much smaller than that of _alata_, differs in various details from the
description of the latter. The principal lateral wings are confined
to the third segment and are united across the dorsum of third somite
instead of involving the anterior border of IV and crossing the latter
above; connecting dorsal fold low and lacking any forwardly directed
process; the wing rises as a high, rounded lobe on each side just
below level of setigerous tubercles, rising high above the middorsal
surface. In addition to the prominent wings on III there is on IV on
each side a much lower ridge or wing paralleling that on III, this not
more prominent above. Unlike those of _alata_, somites II and III are
not confounded laterally but are distinct throughout. Prostomium short.
Tentacles mostly lost in type; rather slender, not long, apparently
in but a single transverse series. Peristomium deeply excavated at
middle below, the bottom of the excavation rounded and the peristomium
produced on each side of this into the usual large lobes. The branchiæ,
as in the genotype and other species, strongly asymmetrically
developed. The right anterior branchia is much the largest, the trunk
very long, with the left anterior much smaller. Of the posterior pair,
the right, unlike that of _alata_, is also much larger than the left
one. In the type the sternal plates are not sharply differentiated.
The manubriate uncini of V have the general form of those in _alata_,
but the bulge below the beak is much larger and more rounded with the
subrostral tooth more obtuse and nearer the middle of the oblique edge;
beak less divergent from manubrium; vertex with three transverse series
of denticles. The color in the abdominal region light fulvous, in the
thoracic darker with a narrow brownish stripe along caudal border of
each segment laterally and ventrally. Type not quite complete caudally,
retaining eighty somites.
Length, 36 mm.; greatest width, 2.8 mm.
Type--M. C. Z. 2, 168.
The wall of the tube is composed of sand and shell fragments.
_Naneva_ gen. nov.
Prostomium short; with numerous tentacular filaments. Uncini avicular
and of same form throughout. Setæ beginning on third somite; tips
simple. Uncini beginning on the fourth somite. No lateral foliaceous
lobes on the anterior segments. Branchiæ two pairs; branched; attached
on somites II and III.
_Genotype_--_N. hespera_ sp. nov.
Differs from Thelepus and Athelepus in having the branchiæ branched
instead of simple and in having the uncini begin on IV.
_Naneva hespera_ sp. nov.
The prostomium forms a prominent upper lip of which the anterior border
is turned upward all along, leaving a deep concavity between it and
the upcurving posterior fold along which the tentacles are attached.
Because of their curled and tangled condition the precise number of
tentacles was not ascertained, but is about twelve on each side; they
are long, some when fully extended being 15 mm. in length. No eyes
were detected in the type. Peristomium forming a lower lip of but
moderate length with straight anterior edge; scarcely twice as long
as the second somite below. First branchia on each side attached to
second somite just in front and mesad of the first setigerous tubercle.
The second branchia attached just caudad of the first on the caudal
region of somite III. Both branchiæ very similar, each presenting
three principal branches of which the most mesal is largest; ultimate
branches numerous, rather short. Capillary setæ beginning on III and
continuing to XXVII. The anterior setigerous processes are in the form
of vertical plates with straight truncate, distal edge; but in going
caudad these become reduced finally to slight tubercles, with the first
about equal to half the intervening space and by the seventh equal
to this space, while in the abdominal region the opposite series are
separated merely by the median furrow. Anterior ventral plates strongly
longitudinally furrowed. Capillary setæ narrowly bilimbate, drawn out
into a very fine simple tip. Uncini, at least for the most part, in two
series both in thoracic and in abdominal region; apparently with mostly
three transverse rows of denticles at vertex; beak long, the sinus with
parallel sides, opposite side of body evenly curved, not distinctly
shouldered. Total number of segments in the type, which is complete,
about one hundred and thirty, of which II to XXVII are setigerous. Body
rapidly narrowed to the eighteenth segment, but only very gradually
thereafter.
Length, near 45 mm.; greatest width, 1.8 mm.
Type--M. C. Z. 2, 169.
Balboa.