320 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 10 



Magelona pacifica Monro 



Monro, 1933, pp. 1048-1049, fig. 2. 



Collections.— U90-41 (1); 1413-41 (1). 



m. pacifica is characterized in having frontal horns on the pro- 

 stomium; its dorsal surface is marked with longitudinal ridges and trans- 

 verse grooves, as originally shown; parapodia have broad, foliaceous 

 lobes in anterior segments already from the first, and in posterior seg- 

 ments. Dorsal and ventral cirri, located at the outer extremities of para- 

 podial rami, are obvious, the ventral cirri slightly the larger. The noto- 

 podial, postsetal lamella is a broad, foliaceous lobe directed downward 

 toward the interramal space; it increases in size posteriorly to the ninth 

 segment. The specialized ninth segment has a similar, though smaller, 

 postsetal lamella and smaller dorsal and ventral cirri. From the tenth 

 segment the lamellae are developed in both rami, take an interramal, 

 though postsetal, position. Dorsal and ventral cirri continue in thdr 

 normal positions, but are increasingly smaller going back. Setae of the 

 ninth segment are long, pointed, with narrow wing. 



Distribution. — AI. pacifica has heretofore been known only from 

 Gorgona Island, Panama, in the intertidal zone (Monro, 1933). The 

 present collections are from Santa Rosa and San Miguel islands, south- 

 ern California, in 14 and 35 fms. 



Magelona pitelkai Hartman 



Hartman, 1944, Hancock Pacific Exped., vol. 10, no. 2. 



Collections. — Tomales Bay, California (several) ; Bolinas Bay, Cali- 

 fornia (1). 



Distribution. — Central California ; at low water line. 



Magelona californica, new species 

 Plate 28, Figs. 10-14 



Collections. — 903-38 (1) ; Mission Bay, California, shore (1) ; 1450- 

 42 (2). 



The general form is long, slender, threadlike; length (preserved) of 

 a complete individual of 108 segments is 27 mm. The dorsum is marked 

 with paired patches, each consisting of fine, black specks; they are distrib- 

 uted immediately within and behind each setal fascicle; similar patches 

 are at the sides of the body, midway between successive parapodia. 

 Anterior segments are slenderer than the first few posterior ones. The 

 distinction between the 2 regions is more or less sharp (pi. 28, fig. 10). 



