NO. 3 HARTMAN : ORBINIIDAE, APISTOBRANCHIDAE, PARAONIDAE 257 



is transitional. Branchiae are first present, though small (fig. 1), on the 

 fifth and increase in size on more posterior segments (fig. 2) to exceed 

 in length the parapodial lobes. They are simple and lingulate through- 

 out. Thoracic notopodial lobes are simple and tapering; the correspond- 

 ing neuropodial lobes are fimbriated from the second parapodium and 

 have up to 15 uniformly small lobes in a single row in a postsetal posi- 

 tion. A subpodial lobe, resembling a ventral cirrus, is present from the 

 sixteenth segment and continues in the abdomen at the lower edge of 

 the neuropodium (fig. 2). A ventral fringe occurs on the last three 

 thoracic, the transitional and the first three abdominal segments. It 

 gradually diminishes thereafter to a subpodial fringe on about the next 

 14 abdominal segments. 



Notopodia have slender pointed setae and a close fascicle of thin, 

 yellow embedded acicula. Abdominal notopodia have furcate setae (fig. 

 5) in which the two tines are unequally long and the investing mem- 

 brane is supported by fibrillae ; the stalk is smooth. Thoracic neuropodia 

 have palisaded ranks of uncini and long, pointed setae. Those of the first 

 four segments are in shorter and thicker series, with 5 to 7 vertical rows ; 

 after the fifth such segment, there are at most three longer transverse 

 rows. Anteriormost uncini are pale, slenderer and less curved than those 

 farther back, otherwise of the same kind. Each has transverse ridges 

 (figs. 3 and 4) at the outer curved side. Long pointed setae are present 

 in a vertical series behind the other setae, or they are limited to slender 

 fascicles at uppermost and lowermost parts of the setal ridge. An inter- 

 ramal cirrus is first present at the thirteenth setigerous segment; it 

 resembles an uppermost lobe of the postsetal neuropodial fringe and is 

 continued back through abdominal segments (fig. 2). 



Distribution. — Orbinia cuvieri is known from European seas (Fau- 

 vel, 1927a, p. 13) and Greenland (Wesenberg-Lund, 1953, p. 56). 



Orbinia johnsoni (Moore) emended 

 Plate 21, figs. 1-4; pi. 22, figs. 1-8 



Aricia johnsoni Moore, 1909, pp. 260-262, pi. 8, figs. 30-33. 

 Orbinia johnsoni Hartman, 1944c, p. 258. 



Collections. — Dillon Beach, Marin County, California, in sandy 

 beach at low tide line, June, 1941 (about 20) ; Tomales Bay, Cali- 

 fornia, in sandy beaches in an intertidal zone (several) ; La Jolla, Cali- 

 fornia, in sandy beach at low tide line (9) ; Mission Bay, California, in 

 sandy beach near entrance to the sea (several) ; Ensenada, Lower Cali- 

 fornia, Mexico ( 1 ) ; Port Parker, Costa Rica, in 3-8 fathoms, sandy 

 mud (2). 



