Part 3

Resembles _exigua_ in having the branchiæ in the form of a series of single, simple filaments but readily distinguished in having each branchia attached at base of parapodium on the dorsocaudal surface just ectad of the notocirrus instead of at the distal end above. The branchiæ begin on the twenty-ninth setigerous somite and continue to about the one hundred and twenty-ninth, decreasing in size at the two ends of the series. In the middle region they are cylindrical, distally rounded, and transparent, and at most do not surpass the distal end of the parapodium, most of these being obviously shorter than this in the preserved specimen. Also decidedly different from _exigua_ in having four lobes at the distal end of each parapodium, two postsetal and two presetal. These are narrowly triangular, distally pointed, with the presetal lobes thicker and more conical and decidedly longer than the postsetal. The short, distally rounded notocirri are attached at the base of the parapodia above in the angle between the latter and the body wall. Neurocirri distally subcylindric, resembling the distal parapodial lobes. The prostomium distinctly ringed to near middle, the basal half showing five rings while the distal half in the type is only vaguely annulate, though with indications of apparently seven nearly fused rings, making the total number twelve. Proboscis long, densely papillose. Type incomplete caudally; one hundred and forty-five segments retained.

Length (not quite complete), 36 mm.; greatest width, 1.3 mm.

Type--M. C. Z. 2, 159.

A note gives the color in life as light, the red blood showing through as usual in the family.

_Glycera verdescens_ sp. nov.

A very small form differing from the two preceding in wholly lacking branchiæ. The parapodia are strikingly different in that the postsetal lobe is either wholly absent, as in anterior region, or is represented by a single, small, pointed process, while there are two presetal lobes which are long and subcylindrical or finger-like and of which the ventral one is ordinarily the larger. The notocirrus is small and occupies the usual place in the angle between the dorsal surface of the parapodium and the body-wall. Neurocirrus slenderly conical, darkened distad as are also the presetal lobes. The slenderly conical prostomium showing twelve annuli. Type at present showing a distinctly greenish tinge. Type incomplete caudally, sixty-nine segments retained, the length being 13 mm., width, 1.1 mm.

Type--M. C. Z. 2, 160.

ARICIIDÆ

_Nainereis hespera_ sp. nov.

This is apparently a smaller species than _longa_ or _robusta_ and is composed of fewer segments. It differs from those species in having the anterior division of the body composed of only nineteen segments and in having the first branchiæ appear on the thirteenth or fourteenth segment. The prostomium is broadly subtrapeziform, narrowing forward and with the anterior margin varying from slightly convex to mesally indented as is the case in the type; dorsal surface nearly flat, simply marked with two furrows, or sometimes with the median caudal region between furrows elevated. Peristomium with anterior margin above more or less concave, its median length about equal to that of the second segment, which is also ordinarily bowed caudad. In the neuropodia of the anterior region the postsetal processes are broad, distally rounded, thick lips which are prominent; in the posterior region these become narrowly conical, elongate, distally pointed processes. The postsetal processes of the notopodia in the anterior region are thick, short cones which increase in length in going caudad, in the posterior region being very elongate. The branchiæ begin on the thirteenth or fourteenth segment as short processes but become abruptly longer, basally thick and distally pointed processes much thicker than the postsetal processes of the notopodia and exceeding these in length; they are widely separated and, while curving in somewhat mesad, do not come in contact, leaving much of the middorsal region naked. They continue to the end of the body. The neuropodial setæ of the anterior region are arranged in three subvertical series and form a patch twice as high (dorsoventrally) as long (cephalocaudally). The stout setæ of the posterior row are mostly four in number, less commonly three or five. These coarse setæ are not at all clavate as in elongata and are not roughened or cross-ridged above the curve as in robusta; the terminal region above the curve longer than in the later species. The setæ of the other series are more curved than in robusta and are abruptly contracted farther from the body, the contraction stronger but the one edge similarly roughened or denticlated with cross lines. At the ventral end of the series a small patch of ordinary, camerated, capillary setæ resembling the notopodials. The body is broad anteriotly and narrows to the posterior end. Dorsal surface flat and the ventral convex as usual. Number of segments in the type one hundred and thirty-six. Color in general pale brown; at black spot at base of each branchia at least those of posterior region, in front and behind and the proximal part of branchia often darkened.

Length, 27 mm.; greatest width, 2.4 mm.

Type--M. C. Z. 2, 161.

_Scoloplos acmeceps_ sp. nov.

Resembling _S. armiger_ (O. F. Müller) in general structure. A less deeply pigmented species easily distinguished from this northern form in wholly lacking the ventral papillæ (neurocirri) present in the latter below the parapodia of about the eighteenth to thirtieth segments. The prostomium is similarly elongate and pointed but is more slender; it is borne at the end of the peristomium which has the form of a truncate cone. The branchiæ begin anteriorly in the same way as very slight elevations and increase quickly to long ligulate forms; but the first one appears on the sixteenth or seventeenth setigerous segment instead of on the twelfth or thirteenth as usual in armiger. The fully developed branchiæ are obviously narrower than typical for the latter species. The lobes of the parapodia are in general similar though they do not become obvious so far forward. In the second division of the body the ventral lobe is similarly elongate and bifid at the tip with the inner or more dorsal lobe the longer; but the lobes are characteristically more divergent, thinner and more slender. The first bifid neuropodial lobes appear on the twenty-first setigerous segment. The dorsal lobe similar in form to that in armiger. Caudal end of all the types missing.

Greatest width, 2 mm.

Type--M. C. Z. 2, 162.

Balboa (Sept. 10, 1917).

FLABELLIGERIDÆ

_Flabelligera haerens_ sp. nov.

This species resembles _F. commensalis_ Moore in the approximation of the neuropodia though these are apparently not so close as in that species and are at no place actually contiguous though nearly so in the extreme caudal region. In front of this they remain a uniform distance apart, which is less than the length of a somite, forward to about the tenth somite from where the rows diverge gradually forward. The notopodia more widely separated, the rows diverging cephalad from near the tenth somite, always much closer to each other than to the neuropodia. Ventral surface flattened or weakly concave, the dorsal surface also flattened but slightly convex, while the sides are convex; the body in part is slightly compressed from side to side, in cross-section subquadrate to subcircular; widest in middle region and narrowing both ways, more strongly so caudad, subfusiform. Collar lobe deeply and widely incised dorsally and ventrally; the lobe on each side bearing a series of numerous long cross-striated setæ which are reddish brown in color and are stouter than the ordinary notopodials. The notopodials are simple, finely tapered, colorless setae. There is a single seta in each neuropodium, this being in the form of a very stout hook; the color is dark throughout; the transverse terminal portion of the hook is longer and more slender and acute than in commensalis and the pseudo-joint is farther proximad of the curved region; the shaft is bent caudad at the level of the joint, the hook proper curving mesad. The entire surface is densely papillose. The setæ of the collar are cloaked by a dense growth of long filiform papillæ; with large clavate tips, these papillæ approximating the setæ in length. The papillæ also cluster densely about the notopodia, these papillæ having similar clavate tips. The papillæ of the general surface of dorsum, venter and sides are much shorter. Color nearly uniform greyish brown. Number of segments in type, forty-nine.

Length, 13 mm.

Type--M. C. Z. 2, 163.

Taken in holdfasts of kelp, August 12, 1917.

CAPITELLIDÆ

_Natomastus angulatus_ sp. nov.

In comparison with N. tenuis Moore, known from San Diego, this species differs in the form of the thorax, which is strongly angulate instead of terete the sides and venter being flat and the dorsum usually but little convex, so that the cross-section is nearly quadrate; also in having the segments and their subdivisions sharply separated with the posterior subsegment in each case much shorter than the anterior instead of equal to it. In the type the posterior thoracic somites are twice or more as long as wide, but in some paratypes the relative length is much less. Thorax narrowed caudad. The abdomen in its anterior part obviously thicker than the thorax in its widest part. The prostomium characteristic, showing two distinct regions, a broad posterior one with convex, anteriorly converging sides and a narrower, subconical, palpoidal terminal part sharply set off from the basal. Segments of abdomen irregularly multiannulate, sulci deep and surface usually appearing strongly rugose and uneven.

Length near 160 mm.; greatest width of abdomen, 1.4 mm.

Type--M. C. Z. 2, 164.

Taken in sand and in growths of eel grass. The color is noted as reddish in life, as usual in the family.

SPIONOIDEA

_Morants_ gen. nov.

Body with an anterior region of fifteen setigerous somites separated from a larger posterior region by a specialized somite, the sixteenth. Prostomium with a lateral process or horn on each side in front, notched in front at middle. Eyes none in genotype. Dorsal cirri present in addition to branchiæ on the first four setigerous somites. Notopodia with simple capillary setæ throughout. Anterior neuropodia with capillary setæ, but others also with crochets. Anal. cirri two.

_Genotype_--_M. duplex_ sp. nov.

_Morants duplex_ sp. nov.

Palpal processes lost from type. Proboscis as protruded short, distally expanded over proximal region. Parapodia dorsolateral in position, the anterior ones very thick. Principal postsetal lobe rising above into a branchial process which is short anteriorly but in posterior region is much longer, slender and subulate. Mesad of the branchial process of each parapodium of the first four pairs is a cirrus or cirriform process. The inferior setæ of the most anterior parapodia' much shorter than the dorsals, strongly curved. In the first notopodial fascia a much stouter, aciculiform, setæ which is uncate. Crochets with strongly narrowed neck; with two curved teeth at distal end above the beak which is decurved; in posterior region few in number, commonly four in a series. Anal cirri slender, filiform, much longer than the preceding branchiæ; one in the type has a short spur near its base. Total number of segments about one hundred and sixteen.

Length, 21.5 mm.

Type--M. C. Z. 2, 165.

Balboa.

The tubes adhere closely to the body. Their walls of fine sand.

AMPHARETIDÆ

_Schistocomus_ gen. nov.

Like Phyllocomus in lacking tentacles and postbranchial spines, in bearing fifteen pairs of fasciæ of capillary setæ and four pairs of branchiæ. It differs from that genus in having the branchiæ of two types, one pair being of the ordinary, smooth, simple, subulate form and the other three with the edges divided, two pinnately, bearing two close series of lamellar branches, and one with an essentially single series of branches in the genotype.

_Genotype_--_S. hiltoni_ sp. nov.

_Schistocomus hiltoni_ sp. nov.

The body has the ordinary general form, being widest near the fifth setigerous segment from where it narrows continuously to the slender, pointed cauda. Dorsum convex, venter less so, the latter with a double median longitudinal furrow in the posterior region. Prostomium projecting forward as a simple hood with rounded anterior corners and the median region of anterior edge nearly straight; dorsal surface in type longitudinally wrinkled. Ventrally the peristomium projects forward between the sides of the prostomium in a conspicuous lobe or lower lip which narrows somewhat distad and has the distal margin convex; surface longitudinally wrinkled. Second somite achaetous. The third bearing the first fasciæ of simple setæ, the sixth the first uncini. Of the pinnate branchia one pair occur on the third setigerous somite and one on the second while the branchiæ with single series of branches in which the branches are less lamellate, are on the second (first presetal) somite, the simple branchiæ arising on the first setigerous somite. The first branchiæ are attached near the middle of the dorsum, the others laterad close above the parapodia. The first and especially the second or simple branchiæ extending forward beyond the anterior edge of the prostomium. Color light fulvous or in part greyish. Number of segments near fifty-five.

Length, 22 mm.; greatest width, 3 mm.

Type--M. C. Z. 2, 166.

Taken at Laguna Beach, Sept. 15, 1917.

The tube in which the type was found is 35 mm. long. The wall is thickened by the adhesion of fine particles of sand, fragments of shell, etc.

TEREBELLIDÆ

_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.

SABELLIDÆ

_Myxicola monacis_ sp. nov.

In size and general appearance resembling _M. pacifica_ Johnson, with the type of which it has been compared. From that form the present one may readily be distinguished in having the ventral median process from the first segment drawn out into a slender entire tip instead of being broad and presenting distally two angles or lobes; the process is furrowed longitudinally and the edges are somewhat turned down. Branchiæ twenty-two pairs. Readily distinguished by the form of the abdominal uncini. These have the general form of those of _pacifica_ but as a whole are longer with the body proportionately more slender and its abvertigial end more rounded; the beak is longer and less divergent, distally curving a little back toward the body; the sides of the sinus parallel. The body in the type is somewhat fusiform, being narrowed both ways from the middle but more strongly so caudad. In a paratype the body is scarcely narrowed cephalad. Body somewhat depressed dorsoventrally, less terete than in pacifica. Total number of segments near seventy.

Length of type, exclusive of branchiæ, 40 mm.; greatest width, 6.2 mm.

Type--M. C. Z. 2, 170.

Taken from holdfasts of seaweeds.

_Potamilla clara_ sp. nov.

The body in general light brown; but ventrally there is a median longitudinal fulvous stripe over the ventral plates. The branchiæ are crossed by a series of dark bands or annuli which fade out proximally, about three distad of the middle of length being deep and distinct. There are nineteen pairs of branchial radioles; barbs numerous, densely arranged to near tip, the naked distal region of axis very short, pale excepting where partially or completely involved by the transverse dark bands. Ventral lobes of collar moderate, rounded, edges a little rolled down; dorsal ends separated; no lateral incisions, being but two-lobed; not produced forward below, lobes rounded and separated. Thoracic segments eight. Ventral plates all rectangular, those of the abdomen divided by the midventral sulcus. Total number of segments, sixty.

Length without branchiæ, 21 mm.; length with branchiæ, 28 mm.; greatest width, 3 mm.

Type--M. C. Z. 2, 171.

Taken on beach at low tide.

_Potamilla omissa_ sp. nov.

The general color is dusky or pale brownish with the anterior ventral plates lighter and the branchiæ rather weakly transversely banded with dark. Radioles of branchiæ in a simple series; seventeen pairs. Collar well developed, produced forward below in two pointed lobes overlapping at the middle. Eight setigerous thoracic somites. Most dorsal thoracic setæ in each fascicle long and finely pointed with wings narrow; the ventral setæ much more numerous, shorter, spatulate, with fine tip. The uncini have the posterior process very short, rounded at the end, much shorter and more slender than the neck, which is rather strongly curved; vertex high and narrowly rounded; beak not strongly depressed. Type incomplete, only seven of the abdominal segments being present.

Length of first sixteen segments, 15 mm.; including branchiæ, 21 mm.; width, 2.5 mm.

Type--M. C. Z. 2, 172.

_Potamilla colorata_ sp. nov.