FISHERY BULLETIN: VOL. 70, NO. 2 



but all limbate setae are broken off so that a 

 complete redescription of C. paucibranchiata is 

 not possible. 



CHONE DUNERI MALMGREN 



Figure 2a, b 



CHONE DUNERI Malmgren, 1867, p. 225.- Hof- 



sommer, 1913, p. 336.- Pettibone, 1954, p. 339.- 



Hartmann-Schroder, 1971, p. 517. 

 CHONE sp. I Banse, Hobson, and Nichols, 1968, 



p. 547. 

 CHONE BIMACULATA Banse and Nichols, 



1968, p. 227.- Nichols, 1968, p. 61. 

 not CHONE DUNERI.- Pettibone, 1956, p. 577 



(a Euchone sp., see Remarks). 



Diagnosis: A Chove of intermediate size with- 

 out ventral shields. Branchial basis somewhat 

 higher than oblique collar. Up to about 10 pairs 

 of radioles, connected for about two-thirds of 

 length by palmate membrane, with narrow, very 

 long free ends. First bundle of setae very small. 

 Conspicuous notopodial lips in thorax. Spatulate 

 setae with pointed tips. Abdominal uncini with 

 broad bases and small accessory teeth. 



Material studied: Point Barrow, northern 

 Alaska, 5 miles offshore, 89 m, 6 Oct. 1949. Col- 

 lected by G. E. McGinitie, identified by M. H. 

 Pettibone (Pettibone, 1954). USNM 23633, 2 

 specimens. 



Paratypes of C. bimaculata, from station 5 of 

 Lie (1968, 3 May 1963). USNM 36280, 4 spec- 

 imens. 



West Sound, Orcas Island, Wash., approx. lat 

 48°36'N, long 112°57'W, 40 m, mud, July 1967. 

 Collected by H. L. Sanders. 1 specimen. Un- 

 published record. 



Additions to the Description: The longest 

 complete specimens at hand, from Point Barrow, 

 are 18 and 26 mm long. In all animals examined, 

 the free ends of the radioles are one-quarter to 

 one-third as long as the entire radioles, tending 

 to be relatively longest on the dorsal side of the 

 branchial crown. Ventrally, about four pairs of 

 nude filaments are found; two pairs are almost 

 as long as the branchial crown and at least some 



have cartilaginous axes. As described by Malm- 

 gren (1867, Plate 14, Figure 75), the collar 

 barely conceals the peristomium so that the 

 branchial base is fully visible. The first (buccal) 

 segment is not clearly distinguishable from the 

 collar in unstained animals. A postsetal girdle 

 of glands is present on the second setiger. Ven- 

 tral shields are absent. The first fascicle of setae 

 is very small in comparison with the following 

 ones. From the second setiger on, notopodial 

 lips are conspicuous. The thoracic neurosetae 

 are winged hooks in Arctic and Puget Sound 

 specimens (see Banse and Nichols, 1968, Figure 

 2g). An anterior abdominal uncinus is shown 

 in Figure 2a. 



The staining pattern of the specimens from 

 Point Barrow (Figure 2b) is similar to that de- 

 scribed by Hofsommer (1913) for an animal 

 from the North Sea. In contrast to the appear- 

 ance in species with ventral shields, the intensity 

 and appearance of stained tissue in C. duneri is 

 uniform around the entire circumference of the 

 thorax and anterior abdomen. Ventrally, the 

 small, weakly dyed fields in the presetal and 

 postsetal rings are present also in the first ab- 

 dominal setigers but disappear gradually by 

 about the tenth abdominal segment. The dorsal 

 pattern is characterized as follows: The median 

 folds of the collar remain white. The unstained 

 rings in the plane of the parapodia bend rear- 

 ward on the dorsal surface similarly to but less 

 pronounced than in C. infimdibuliformis (Fig- 

 ure lb) . Weakly stained fields are present with- 

 in the presetal stained rings of the thorax (cf. 

 Hofsommer, 1913, text figure h) ; they extend 

 laterally on the abdomen to the level of the neu- 

 ropodia. Consequently the presetal rings of the 

 anterior abdomen are nearly split in two. Oc- 

 casionally, the postsetal rings are equally split 

 but this is a condition which may occur also in 

 other species without it having been noted here- 

 in. In most of the specimens from Washington 

 which are smaller and in part not as well pre- 

 served, the pattern agrees but in some the dark 

 longitudinal midventral strip is less conspicuous 

 than in Figure 2b. 



Remarks: Earlier authors have apparently 

 not noted the glandular ring on the second tho- 



466 



