COMPLETE HARTMAN: POLYCHAETES FROM CALIFORNIA 47 



Hesperonoe laevis, new species 

 Plate 1, figs. 1-6 



Numerous collections were taken in shallow ocean bottoms, largely 

 from an association of Listriolobus pelodes Fisher off Santa Barbara, 

 California, and others from adjacent areas of southern California. The 

 type collection is from Velero IV Station 5400, in 42 meters, where 31 

 individuals were taken in a single grab; other large concentrations are 

 from Stations 5531 (12 specimens), 5410 (10), 4723 (8), 4983 (7) ; 

 other stations had fewer individuals. 



This is a small broadly depressed species; larger individuals measure 

 20 mm long and 8 mm wide. The elytra completely cover the dorsum 

 (pi. 1, fig. 1). The prostomium is darker than the body, which is pale. 

 Elytra are oval to subcircular in outline and pale, with a reddish brown 

 mottling all over but most concentrated at the subperipheral posterior 

 part. The prostomium is dusky gray and is medially marked with a 

 longitudinal fissure extending through most of its length. There are 4 

 dark circular eyes; the anterior pair is larger and located just in front 

 of the widest part of the lobe ; the posterior smaller eyes are located near 

 the posterior margin of the prostomium. The median antenna is more 

 than twice as long as the short, lateral ones, which are about half as long 

 as the prostomium (PI. 1, fig. 1). 



The first setigerous segment has large, bushy notopodial fascicles and 

 smaller neuropodial bundles; the notopodial lobe is shorter than the 

 corresponding neuropodial one. Thereafter the notopodial lobe is the 

 less conspicuous. Setae of both rami are of two kinds. Acicula are single 

 in a ramus, yellow, thick, and may project from the ends of the parapodia 

 for a short distance. Notopodial setae include longer, slenderer (PI. 1, 

 fig. 5) and shorter, thicker (PI. 1, fig. 6) ones, transversely pectinated. 



Neuropodia terminate distally in a digitate superior lobe (PI. 1, fig. 2) 

 above the emergence of the aciculum. The setae consist of a few (about 8) 

 supra-acicular, strongly pectinated setae (PI. 1, fig. 4), and a larger, 

 subacicular fascicle consisting of about 15 thicker, nearly smooth and 

 shorter setae (PI. 1, fig. 3). Elytra number 15 pairs and completely 

 cover the dorsum ; each is a large, thin disk. The first pair are subcircular 

 or slightly oval in outline and have entire margins. The dorsal surface 

 is pale or white with gray pigment arranged in a circular area over the 

 outer half and a small white area over the elytrophoral scar; a gray 

 crescentic area is present along the inner half of the surface. Other elytra 

 are slightly reniform or excavate at the anterior margin ; the margin is 

 nearly smooth except for an occasional digitate papilla. Microtubercles 

 are limited largely to an anteromedian area in front of the scar. 



