1 86 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



same length; the ventral much shorter. Palpi long, terete, smooth, 

 usually twisted and coiled in preserved specimens. Spoon-shaped organs 1 

 small, somewhat shorter than ventral peristomial cirrus. 



First pair of elytra whitish, rhomboidal; all the rest (fig. 61) reniform, broader 

 on somites 2-27, narrower back of this point; papillate (fig. 61a) on ventro- 

 lateral margin; with minute, transparent tubercles (fig. 616), and with two 

 kinds of pigment — intra-cellular and cuticular (fig. %\b). Elytra borne on 

 somites 2, 4, 5, 7. . .27, 2S, 29, and on every succeeding somite. 



Parapodia (fig. 64) elongated, strongly biramous at tip, all furnished with 

 a terete, slightly tapering, branchial appendage, arising from external edge of 

 elytrophore, constricted at its base, its tip usually in contact with the dorsal 

 side of the parapod; fringed with long cilia on one side. Each branchia, be- 

 ginning with the twenty-fifth, has a black pigment spot on its upper side, 

 nearer the base in the anterior, but nearer the tip in the posterior branchia. 

 This spot disappears on the most posterior branchiae. Between the base of 

 the branchia and the point where the parapod divides occur three ciliated 

 cushions (fig. 64), of which the middle is twice the width of the other 

 two. Tip of anterior ventral rami with several finger-like processes. 

 Dorsal setse very long, capillary, dorsally curved, serrulate on two borders 

 (figs. 64, 64/, 645'). Ventral setae (figs. 64, d\a-e) of four kinds: (1) a small 

 fascicle of simple, spirally frilled setse, projecting in the fissure between the 

 rami (fig. 64^); (2) next to these three or four very stout, jointed seta? with 

 moderately long, toothed appendage (fig. 64c, d); (3) stout, jointed setae with 

 very short appendages (fig. 646); (4) slender, articulated setae in lowest por- 

 tion of series (fig. 64a). Ventral cirrus not reaching tip of parapod; with 

 wing-like expansion on dorsal aspect, and slightly moniliform near tip. 



Measurements. — Length of full-grown specimen, 95 mm.; width., 7 mm. 



Sthenelais fusca frequents crevices under stones and 

 among the rhizomes of the "eel-grass" (Pkyllosftadix), 

 along a large portion of the California coast. It is ap- 

 parently a rare species, for we have found thus far only 

 four specimens: two in the vicinity of San Pedro, and two 

 in the vicinity of San Francisco (at Pillar Point, San Mateo 

 County, and at Bolinas, Marin County). All the speci- 

 mens were taken at low-water mark during a run of low 

 tides, so it is probable that beyond the littoral zone it occurs 

 much more abundantly. 



Three of the specimens are females, turgid with nearly 

 ripe eggs of a bluish gray color. They were collected in 

 June, July, and November. 



1 These are described at length by Claperede (Ann. Chaet. du Golfe de Naples, 1867, 

 P- 399)- 



