1 68 CALIFORNIA ACADEMY OF SCIENCES. [Proo 3D Ser. 



white spot just over the elytrophore, with a black, gray, brown, or orange 

 fleck in front; remainder of elytron more or less densely mottled with spots 

 of the same color as the general pigmentation. 



Coloration highly variable, but in all cases the fundamental or ground color 

 is white. This is overlaid by pigmented areas of iron-gray, tawny, brown, 

 yellow, or orange. Melanistic specimens are common, in which the iron- 

 gray is intensified to almost jet black, and even the ventral side is dark. 



Each somite marked dorsally with a transverse dark bar, in front of which is a 

 lighter bar of the same color, broadly interrupted in the median line, and 

 often broken transversely by a fine white stripe midway of its width. Ven- 

 tral side either unpigmented or washed with ashy in melanistic individuals; 

 this dark tint accentuated by a narrow, white, mid-ventral line. 



Measurements. — Length of large commensals, 75 mm.; width across mid- 

 dle of body, 1 1 mm. ; length of full-grown non-commensals, 57 mm. ; width 

 across middle of body, 9 mm. 



This fine Polynoid is the commonest of its family along a 

 large portion of our coast. I have obtained it in abund- 

 ance between tide-marks at Pacific Grove and in the vicin- 

 ity of San Francisco, both in the bay (at Lime Point and 

 Point Cavallo on the northern side of the Golden Gate) 

 and along the outer shore. I have also numerous speci- 

 mens from localities further north — Point Arena, Cape 

 Mendocino, Humboldt Bay, Trinidad, and Puget Sound. 

 How much further north and south it extends I am unable 

 to say, but have never found it at San Pedro or San 

 Diego. 1 Undoubtedly it ranges much further northward 

 than Puget Sound. I am confident that the species col- 

 lected by J. K. Lord at Esquimalt and described by Baird 

 under the names Halosydna insignis and H. gmbei are 

 varieties of this form. 



I have never dredged this species, and am ignorant of 

 its bathymetrical range. Northward, at any rate, it extends 

 a good deal below low-water mark. I have specimens taken 

 from the buoy at Point Arena, for which a depth of 15 

 fathoms is recorded; and others from Humboldt Bay, taken 

 at a depth of 9% fathoms. 2 



Halosydna brevisetosa is probably entitled to the distinction 



l A single specimen was collected by Mr. F. W. Bancroft at Avalon, Santa Catalina 

 Island, in August, 1893. Avalon lies south of San Pedro about 25 miles from the main- 

 land. 



2 These specimens were kindly presented to the University by Capt. Frank Curtis, 

 United States Light House Inspector, along with other Invertebrata from the buoy-chains. 



