Hesperophyllum gen. nov.
Similar in general to Notophyllum and Austrophyllum but differing especially in having the ventral cirrus of the second segment flattened and foliaceous and strongly asymmetrical. It is like Notophyllum and unlike Austrophyllum in having the first segment dorsally reduced.
Genotype.—H. tectum sp. nov.
Hesperophyllum tectum sp. nov.
The first segment dorsally reduced. Ventral tentacular cirrus of second somite of a thin or foliaceous and asymmetrical form. Other tentacular cirri subcylindric, reduced distally to a pointed tip, that of I about half as long as the dorsals of II and III. Paired tentacles short, proximally thick and convexly bulging, abruptly narrowed to an acute tip with incurving sides. Unpaired tentacle situated between eyes in line connecting their centers, nearly of same length and size as the first tentacular cirri and about as long also as prostomium; annulate. Prostomium shortly subcordate, well rounded in front, incurved caudally. With very large cirri of which the dorsals widely overlap in the middle and thus completely cover the dorsum, the prostomium normally also being wholly concealed from above. The neurocirrus of a typical parapodium is attached by a broad base extending from a pronounced ventral swelling or flange (neurocirrophore) across the caudal side of the parapodium to its dorsal edge and projects farther dorsad of the parapodium than ventrad, the dorsomesal end widely rounded; much broader dorsoventrally than long, with the free edge evenly rounded. The notocirrophore in a thick rounded body arising from the base of the parapodium proper and showing the notopodium as a proportionately much smaller lobe on its ectal side; the style is attached about its caudal half-circumference and is broadly subreniform with the free margin coarsely crenulate or wavy, its mesal limb widely overlapping that of the opposite notocirrus and its ectal one overlapping the neurocirrus. Surface of cirri and of somites, especially ventrally, densely covered with very fine brown dots or points. Number of segments in type, near seventy-three. Body narrowing caudad, becoming narrow and pointed at posterior end. Proboscis unknown.
Length, 19 mm.
Type—M. C. Z. 2, 143.
Dredged. Brown in life, this color being also retained in the preserved type specimen. A paratype has a greenish cast. This species suggests Notophyllum imbricatum Moore in the large imbricated notocirri covering the dorsum but in the latter all the tentacular cirri are of the elongate, symmetrical, evenly tapering form characteristic of its genus. Imbricatum similarly presents nuchal appendages, but these are three in number on each side and slender, instead of two broad, subelliptic lobes. The neuropodium is distally narrowed instead of broad, the head is differently formed, and various other differences are present throughout.
Steggoa gracilior sp. nov.
This is a small and slender form noted as green in life and also retaining this color after preservation in alcohol. It agrees in general with Steggoa, the first segment being normally developed above and distinct from the prostomium though not so clearly separated as usual, suggesting a tendency toward the Hypoeulalia condition. Prostomium a little longer than wide, narrowed anteriorly, sides convex; a short lobe, rounded in front and bearing the four tentacles, is set off by a weak constriction from the basal part. Unpaired tentacle situated well caudad, more slender than the paired ones but nearly as long. Eyes not detected. Ventral tentacular cirrus of II of a thick, leaf-shaped form, sublanceolate in outline and much like the notocirri. The other tentacular cirri longer and filiform. Notocirri in outline lanceolate, characteristically exceptionally thick in proportion to width so as at times to appear nearly subconical. Neurocirri much smaller; similarly proportionately thick and at times subconical. Body slender, strongly narrowed from the middle toward both ends. The proboscis densely and uniformly papillose throughout. Number of segments near one hundred and twenty-three.