138 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 22 



Neoheteromastus lineus, new species 

 nr. Barantolla sp. Hartman and Barnard, this volume, p. 45, in part. 



The type is selected from San Nicolas Basin (Sta. 5931) ; other indi- 

 viduals come from San Nicolas and Santa Catalina Basins. This is a 

 small, nearly smooth, unadorned capitellid. None is posteriorly complete 

 but total length may not exceed 25 mm. The prostomium is a short, 

 small, semicircular lobe without eyes. The peristomium is a smooth, 

 weakly biannulate ring about one and a half times as long as the first 

 parapodial segment. The everted proboscis is subglobular, externally cov- 

 ered with coarse papillae resembling recurved spinelike cusps directed 

 orally. 



The thorax has long, distally pointed setae in the first 8 notopodia 

 and long handled hooks in the last 3 notopodia. A neuropodium is lack- 

 ing from the first setigerous segment; this is followed by 6 neuropodia 

 with pointed setae and 4 with long handled hooks. The hooks have a 

 large fang, surmounted by a series of fine teeth and are distally covered 

 with a rounded hood. Branchiae have not been observed and are presumed 

 to be absent. 



Neoheteromastus lineus has been recovered only from San Nicolas 

 and Santa Catalina Basins in subsill depths; it may be considered a deep 

 water species. 



Genus MEDIOMASTUS Hartman, 1947, extended 

 Type Mediomastus californiensis Hartman, 1947 



The generic diagnosis is here extended to include species having 10 

 thoracic setigerous segments in which the first 4 to 6 have pointed setae, 

 and the last 6 to 4 have long handled hooks. The thoracic formula thus 

 reads: thorax with 4 to 6 setal segments in notopodia, 6 to 4 hooked 

 segments in neuropodia. The abdomen has only long handled hooks ; 

 branchiae are believed absent. 



Mediomastus glabrus, new species 



nr. Barantolla sp. Hartman and Barnard, this volume, pp. 45, 47-49, in 



part. 



The type is selected from Santa Catalina Basin (Sta. 2850) ; other 

 individuals come from Santa Catalina, San Nicolas and Tanner Basins. 

 Largest specimens measure 10 to 15 mm long by 0.5 mm wide; none is 

 posteriorly complete but posterior fragments are available. Separation 



