162 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 22 



having thicker, elevated bases. Those of the first 10 segments are lateral, 

 below the notosetal tuft. 



All setae are distally smooth, broadly limbate and of a single kind, 

 except that some are shorter, others longer. Uncini are short, avicular, 

 have a large fang surmounted by a rostrate beak with many small teeth 

 forming a broad head. 



Leaena caeca differs from other species of the group (see Hessle, 

 1917, pp. 196-199) in that lateral lappets are weakly developed and 

 present on only 2 segments. Leaena videns Chamberlin (1919, p. 18), 

 from southern California in littoral zones, is another species; it has 

 transverse bands of eyespots behind the tentacular base. 



Leaena gracilis Moore (1923, pp. 191-192, pi. 17, fig. 8) from off 

 Point Pinos lighthouse, in 204-239 fms, in gray mud, has 15 thoracic 

 setigerous segments and is probably referrable to Lanassa Malmgren. 



Family TRICHOBRANCHIDAE 

 Genus Terebellides Sars, 1835 



Terebellides stroemi Sars, 1835 



Hessle, 1917, pp. 137-138. 



Berkeley and Berkeley, 1952, pp. 75-76, figs. 152, 153. 



Numerous individuals were collected from nearly all basins. Repre- 

 sentatives are typically smaller than their shallower water relatives, and 

 the pectinated branches of the branchia tend to be less compact than in 

 the littoral form. They are here regarded as the cosmopolitan species, 

 known from all major oceans (Berkeley and Berkeley, 1952, p. 76). 



Family SABELLIDAE 



Genus POTAMETHUS Chamberlin, 1919 



Potamethus mucronatus (Moore) 1923 



Notaulax mucronata Moore, 1923, pp. 243-245, pi. 18, figs. 43, 44. 



Berkeley and Berkeley, 1951, pp. 333-334. 



Numerous individuals come from San Pedro, Santa Monica and 

 Santa Catalina Basins. Tubes are silt-covered, some adorned with long 

 sponge spicules set on end, causing a spiny appearance, others nearly 

 smooth. In some instances the tubes are clustered and loosely attached 

 to one another by basal strands. Larger specimens measure 57 mm long 



