NO. 2 HARTMAN, BARNARD: BENTHIC FAUNA OF DEEP BASINS 115 



forms conspicuous thin wings at the sides of the prostomium. Branchiae 

 number 3 pairs and are entirely bipinnate. The first parapodial segment is 

 rudimentary and has few setae. The next 4 segments have conspicuous 

 foliaceous lobes which are reduced farther back. Hooded hooks are 

 present from about neuropodium 20, at first few in a fascicle, and within 

 5 segments replace about half of the pointed setae; they alternate with 

 pointed setae through about segment 52. 



Specimens taken from basin and shelf depths of southern California 

 agree with these accounts, but those from shallower bottoms are larger, 

 usually have prostomial eyes, weakly to well developed, and are strikingly 

 pigmented in life (those from basins are pale or translucent). The best 

 pigmented specimens have 8 to 10 transverse bars of alternating black 

 and yellow pigment on the branchial pinnae; this fades out in preserva- 

 tives. A mud-walled or any other kind of tube has not been observed. 



The diagnostic characteristics, as herein defined, are illustrated in the 

 accompanying figures (Plate 9, figs. 1-5) based on a specimen from the 

 upper end of Redondo canyon (Sta. 2193 in Hartman, 1955, p. 45). 

 The anterior end has 3 pairs of large, bipinnately divided branchiae 

 (Plate 9, fig. 1). A ninth parapodium, in anterior view, shows the 

 arrangement of setae, hooks and genital spines (Plate 9, fig. 2). These 

 spines are punctate along their free length (Plate 9, fig. 5). Hooded 

 hooks are distally curved, have a large fang and are surmounted by 4 

 teeth in 2 rows (Plate 9, figs. 3, 4). 



Prionospio pinnata has been reported from all major oceans and from 

 shallow to eurybathyal depths (Fauvel, 1953, p. 324). In southern 

 California its greatest concentrations are in shelf and slope depths and 

 in sediments of olive-green silty muds. 



Prionospio nr. cirrifera Wiren, 1883 

 Berkeley and Berkeley, 1952, pp. 28-29, figs. 52, 53. 



Specimens come from San Pedro and Santa Catalina Basins. A small 

 one measures about 10 mm long by 1 mm wide. One has 6 pairs of 

 slender, cirriform branchiae inserted on setigerous segments 2 to 7 ; 

 another has 8 pairs of branchiae on setigerous segments 5 to 12, suggest- 

 ing that a total of 1 1 pairs were originally present. The prostomium is 

 broadest in front and approximately T-shaped ; it is dorsally depressed 

 and lacks eyes. A caruncle extends back to the end of the first or second 

 segment. The peristomium forms a pair of lateral lobes at the sides of 

 the prostomium. 



