46 HARTMAN 



Oivenia fusiformis collaris, new subspecies 

 Plate 2, figs. 6, 7 



Owcnia sp., Hartman, 1955, p. 179 



Collections: Many specimens come from San Pedro Basin, Cali- 

 fornia, in 5 to 48 fms (see Hartman, 1955, p. 179). 



The tube is fusiform, with the distal ends attenuated ; externally it 

 is closely covered with sand and shell particles. The largest measure 

 about 90 mm long and 8 mm wide near the center. The animal preserved 

 in the tube is about 54 mm long and 3.12 mm across. The branchial 

 crown in larger individuals is greatly branched so that there are well 

 over a hundred tips; the branching is close and the entire crown very 

 short for its great width. 



A conspicuous, thin, membranous, entire thoracic collar that is uni- 

 formly high all around, except for a pair of ventrolateral notches, con- 

 ceals as much as half of the branchial base, as well as the dark brown pig- 

 ment band that separates the crown from the thorax. A similar dark 

 pigment is present on the crown as a band partly encircling the sub- 

 terminal filaments, best seen on the inner side of the crown. A pair 

 of darkly pigmented, crescentic areas resembling eyes is present on the 

 ventral base of the crown on its outer side. A large dark brown, shield- 

 shaped area is present on the dorsal side of the thorax between the 

 setigerous fascicles of the first three segments ; it extends nearly across 

 the dorsum and is limited to this region. 



The third setigerous segment has setal fascicles which are smaller 

 and shorter than those of the first two and fourth fascicles ; they lie about 

 midway between the second and fourth fascicles and are smaller than 

 the others. Uncinal ridges resemble those of the stem species. The uncini 

 differ in having two very long, straight teeth (fig. 6) set in a nearly 

 straight line (fig 7) ; there is no shoulder at the subdistal end of the 

 shaft, such as occurs in the stem species. 



O. fusiformis collaris differs from the stem species in having a high, 

 thoracic, membranous collar ; the uncini have much longer teeth and 

 lack a shoulder. The subspecific name refers to the thoracic collar. 



Distribution: This subspecies occurs in shallower depths of San Pedro 

 Basin, California, associated especially with sandy muds. 



