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.