68 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 25 



Ophiodroftius pugcttensis ranges in the northeast Pacific Ocean in 

 intertidal zones and in shallow ocean depths. 



Genus Oxydromus Grube, 1855 

 Type O. fasciatus Grube, 1855 



Oxydromus arenicolus La Greca, 1946, glabrus, new subspecies 



Oxydromus arenicolus La Greca, 1946, pp. 273-276, figs. 4-9. (stem 

 species) 



Collections. Hundreds of specimens come from shallow shelf benthos 

 of southern California, north to Tomales Bay, California. 



The body is pale, uniformly unpigmented and resembles that of 

 O phiodromus pugettensis, with which it is frequently taken, in size, 

 general shape and proportions. The two are most easily distinguished 

 in that this one has parapodia distinctly biramous, and it has 8, instead of 

 6, pairs of buccal cirri. The everted proboscis has a circlet of 10 widely 

 spaced, triangular papillae, whereas that of O phiodromus pugettensis has 

 a circlet of pilose fringe. 



The prostomium is quadrate, about twice as wide as long, and has 2 

 pairs of eyes, the two on each side near together on the posterior half 

 of the prostomium. The 3 prostomial antennae are located at the frontal 

 margin of the lobe, with the paired ones nearly as long as the prostomium 

 and the median one less than half as long. The palpi are nearly as long 

 as the paired antennae and directed forward. The everted proboscis is 

 cylindrical and terminates in 10 widely spaced papillae; there are no 

 jaws. 



The 8 pairs of tentacular cirri are either distinctly articled or the 

 joints are obscure. Parapodia are biramous and the notopodium is both 

 slenderer and shorter than the neuropodium. The embedded acicula are 

 pale to dark amber in color, occur singly in a ramus and are only slightly 

 emergent from the distal end of the acicular lobes. Notopodia have 

 fascicles of long, slender, acicular setae. Neuropodia have long ap- 

 pendaged, composite falcigers in the upper part of the fascicle, and 

 gradually shorter, but similar, ones in the subacicular part of the series. 

 Dorsal and ventral cirri are smooth, cirriform, not articled. 



The subspecies, O. arenicolus glabrus, differs from the stem O. areni- 

 colus La Greca (1946) from the Mediterranean Sea, in that tentacles 

 and cirri are smooth instead of articled. The ventral cirri of glabrus are 

 slender, cirriform, instead of thick, tapering. 



