124 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 25 



of a single kind and attached to the membrane so as to cover most of 

 the lower side. The membrane is distally prolonged and deeply incised, 

 shown in PL 29, fig. 1, in dotted line beyond the filaments. The prosto- 

 mium is a small conical lobe ; it has 4 eyes located at its greatest elevation. 

 The mouth is a large triangular aperture between the palpal bases. 



The first parapodium (PL 29, fig. 4) has long, slender papillae in 

 both notopodia and neuropodia, chiefly postsetal in position. The noto- 

 podium has about 10 very long, slender, cross-barred setae and the 

 neuropodium only about 4 similar setae. The next several parapodia 

 are similar but the rami become farther apart and the lengths of setae 

 diminishes posteriorly. The sixth parapodium has the proportions shown 

 in plate 29, fig. 3. 



Notopodial setae are slender and distally pointed throughout the body ; 

 the length/width relations of the cross-bars varies little (compare in 

 plate 30, figs. 1, 2, 6 and 5). Neuropodial setae in anterior segments 

 are much like notopodial setae. In median segments they are gradually 

 thicker and by segment 78 they become falcigerous (PL 30, fig. 6). 

 Farther back they are gradually thicker (PL 30, figs. 7-9) and fewer 

 in a fascicle ; their distal ends are entire. 



Piromis gracilis differs from other species of the genus in having 

 setae largely of the long, slender, distally pointed kind ; falcigerous, 

 distally pointed setae are present in postmedian neuropodia. The oral 

 tentacular membrane is only moderately prolonged and medially incised. 

 It is known only from western Mexico and Guatemala. 



Family CAPITELLIDAE 



Four closely related species occur commonly in shallow ocean bottoms 

 of San Pedro and Santa Monica Bays, usually in areas of waste dis- 

 charge. The four may occur in the same grab sample (VELERO IV 

 Sta. 5027, 1.9 mi from Point Fermin, California, in 38 fms, in dark 

 black silty sand) ; usually only one is present, indicating a correlation 

 with ecological and distributional factors. The species are here briefly 

 diagnosed, based largely on a sample in which all four occurred. 



Key to Capitella-LiKE Species 



1. First visible segment without parapodia 2 



1. First visible segment with parapodia and setae .... 3 



