COMPLETE HARTMAN: POLYCHAETES FROM CALIFORNIA 129 



This species constructs characteristic tubes; they are closely spiralled 

 in one direction for about half their length, and in the opposite direction 

 for the other part. Tubes are friable, usually reddish brown, and found 

 in sediments of sandy silt. 



S. crassibranchia is considered distinct from S. bairdi (Malmgren) 

 which has been reported from southern California (Berkeley and Berke- 

 ley, 1941, p. 54) ; the latter has uncini of another kind, in which the 

 main fang is surmounted by more numerous teeth in 3 rows. 



S. crassibranchia is known only from southern California. 



Family SABELLIDAE 



Genus Distylidia, new genus 



Type D. rugosa (Moore) 1904 (as Distylia) 



This genus is most clearly characterized by its rugose folds in the 

 posterior part of the body; they cover an extensive area on the dorsal 

 surface and fade anteriorly. The branchial crown is large, at the base 

 spirally coiled with about one and a fourth turns ; radioles are numerous, 

 55 or more on a side, and provided with crowded double rows of eye- 

 spots in irregular distribution. The collar is prominent and two-lobed. 

 Thoracic setigerous segments number 8, and abdominal segments more 

 than 100. Thoracic notosetae are longer, slightly limbate, to shorter, 

 more broadly limbate, but the transition is gradual. Thoracic uncini 

 are avicular and accompanied by pick-axe hooks. 



Distylidia rugosa (Moore) is known only from southern California. 

 Another species, reported as Bispira rugosa monterea Monro (1933, p. 

 1076) from Balboa, Panama, is congeneric, and requires a new specific 

 name. It was first considered to be the same as Distylia monterea Cham- 

 berlin (1919) from California; this has been referred to Eudistylia 

 polymorpha (see Hartman, 1959b, p. 543). The species from Panama 

 is here renamed Distylidia monroi, new name. It differs from D. rugosa 

 (Moore) in having only 2 or 3 pairs of eyes and in the character of the 

 thoracic collar. 



Genus Potamilla Malmgren, 1866 



Type P. neglecta (Sars) 1851 



Potamilla sp. 



Collections. Several individuals come from southern California in 

 shelf depths. 



