170 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D See. 



strong upper bristle in the ventral series — a characteristic 

 very apparent, in P. gigas, even to the naked eye, and 

 probably of advantage in crawling within the tube. An 

 unlooked-for characteristic is the heavier pigmentation of 

 commensals, and the more uniform distribution of pigment 

 over the body. I have one specimen from Humboldt Bay 

 which is almost entirely black, and has the largest and 

 thinnest elytra I have ever observed in this species. 



I have not detected a tendency in northern specimens to 

 be larger than those from near the southern limit. Two 

 specimens from Puget Sound, while of generous dimen- 

 sions, do not equal the largest obtained at Pacific Grove. 



Polynoe reticulata, sp. nov. 



Plate VII, Figs. 32, 41, 41a; Plate VIII, Figs. 47, 47a, 476. 



General aspect very nearly like P. brevisetosa. Form oblong-linear, taper- 

 ing gradually and about equally at both extremities, broadest midway of its 

 length. Somites 37; pairs of elytra 18, on somites 2, 4, 5, 7.... 27, 28, 30, 



31, 33- 



Prostomium (fig. 32) slightly longer than wide, deeply and broadly fissured 

 longitudinally, globose, constricted at base; the basal joint of tentacle set 

 into this fissure. Eyes four, anterior pair considerably wider apart than the 

 posterior, just in front of widest region of prostomium, laterally directed. 

 Posterior pair slightly smaller, near base of prostomium, dorsally placed. 



Anus dorsal, in somite 35. 



Elytra large, thin, orbicular (first pair) to irregularly reniform (fig. 41); all 

 smooth except first two or three pairs, which have small conical tubercles 

 (rarely these are present on all the elytra); sparingly ciliate on external margin. 

 The elytra increase gradually in size from the first pair backward, and at- 

 tain their maximum about the twelfth pair. The first pair are often scarcely 

 half the diameter of the broadest. The upper surface of the elytron is closely 

 punctate or pitted with little rounded or irregular cavities, between the 

 orifices of which lie the epithelial cells, the latter forming a sort of reticulation 

 or network (fig 41a). 



Parapodia (fig. 47) robust, biramous; dorsal ramus very small, with setae 

 of two sorts (fig. 47<5): short, strongly curved ones, which are uppermost, and 

 a small fascicle of long, slender, gently curving ones, which reach bej^ond the 

 tip of the ventral ramus. 



Ventral seta? toothed at tip (fig. 47a), serrated for a short distance below the 

 point, rather short and stout. 



Cirri smooth, slightly thickened below the point, gradually tapering. Anal 

 cirri short, almost conical, not longer than posterior dorsal cirri. Antenna 

 inserted at level of base of tentacle, shorter than tentacle. Peristomial cirri 

 not different from average dorsal setae. 



Palpi slightly thickened near the point, which is fine and filamentous; mi- 



