NO. 3 HARTMAN : ORBINIIDAE, APISTOBRANCHIDAE, PARAONIDAE 281 



Collections.— 885-38 (1) ; 888-38 (1) ; 1021-39 (1) ; 1327-41 (1) ; 

 1450-42 (1); 2012-51 (3); 2113-52 (10) ; 2125-52 (9) ; 2126-52 (5); 

 2153-52 (5) ; 2312-53 (12) ; 2445-53 (21) ; Osoflaco and Oceano, San 

 Luis Obispo County, California (2, collected by Conrad Limbaugh, 

 1955). 



In individuals from California the thorax consists of 19 to 22 seti- 

 gerous segments ; it is depressed through most of its length. The next two 

 segments are transitional (fig. 3). The prostomium is acutely pointed 

 and prolonged so that it is about three times as long as wide at the base ; 

 there are no eyes; nuchal slits are visible at the sides of the posterior 

 margin. The peristomium is about as long as the first setigerous segment. 

 Branchiae are first present from the twelfth to sixteenth setigerous seg- 

 ment or not before segment 24 (1327-41). The first eight or ten pairs 

 are small, but they gradually enlarge and stand erect over the dorsum. 

 The lateral fimbriae are most conspicuous at greatest branchial develop- 

 ment, the subdistal enlargement is asymmetrical and the distal tip is 

 smooth (figs. 3, 4). 



In about the first 16 parapodia the thoracic neuropodia have a single 

 papillar lobe (fig. 2) in postsetal position. Between segments 14 to 17 

 a second small lobe is present below the middle one and thereafter both 

 lobes become longer and extend behind the larger neuropodial uncini. 

 In addition a smaller, prolonged lobe some distance below the para- 

 podium is present (fig. 1). A purplish pigment spot is visible between 

 the base of the parapodium and the subpodial lobe. Between segments 19 

 to 32 (or only to 28) the subpodial lobe increases, is largest on about 

 segment 26 (fig. 3), and decreases to absence after segment 32. The 

 neuropodium has only a postsetal lobe to segment 22. 



The abdominal region begins at segment 20 to 23 ; it is marked 

 especially by an abruptly slenderer neuropodial fascicle and more pro- 

 longed setal lobes (fig. 4) and broad neuropodial flanges. The flange 

 is first noticeable on about segment 18 as a small dark spot between the 

 ventral cirrus and the subpodial lobe (fig. 3) ; thereafter it enlarges, 

 becoming padlike through a few segments and a flange in abdominal 

 segments. The dark spot (persisting in preservative) is visible on the 

 posterior face of the flange. Anterior thoracic notopodia have a long 

 triangular postsetal lobe and neuropodia have a short papillar lobe near 

 the midlength of the ridge (fig. 2). 



Notopodia have full fascicles of pointed setae. Neuropodia have 

 similar pointed setae and ridged uncini (figs. 6, 7). The transverse ridges 

 extend across the outer curved side of the uncinus and number 4 or 5 



