430 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.10 



L. pallidior was originally compared with Notomastus tenuis and 

 Notomastus angulatus (see Clistomastus tenuis), hence is believed to 

 lack special branchiae. The arrangement of parapodial parts, the sti-uc- 

 ture of hooks, the distribution of lateral organs, nephridia or genital pores, 

 are not known. Without more information about the species, comparison 

 with others is not possible. 



Distribution. — Originally described from Pacific Grove, California, 

 this has been reported also from Vancouver Island, British Columbia, in 

 89 meters (Berkeley, 1942, p. 198). 



Genus Dasybranchus Grube 

 Type D. caducus (Grube) 



The thorax consists of 14 segments of which the second to fourteenth 

 are setigerous and provided with only pointed setae in notopodia and 

 neuropodia. The abdomen is provided with only hooded hooks. 

 Branchiae are either retractile or stationary; they are simple lobes or 

 progressively lobed to form composite tufts. They arise from the epithe- 

 lium near the superior and posterior edge of abdominal neuropodia. Lat- 

 eral organs are more or less conspicuous; they are sometimes difficult to 

 distinguish in external view but are probably present in both thorax and 

 abdomen. Genital apertures are present on some abdominal segments. 

 Nephridial pores occur on the thorax and abdomen. 



The abdominal hooded hooks of the various species of the genus show 

 interesting similarities. The typical arrangement is for the large fang to 

 be surmounted by a single row of 3 teeth. In D. lumbricoides the teeth are 

 low, well separated from each other, in D. glabrus they are partly fused 

 and in Z). lunulatus they are more or less completely fused for their entire 

 length. In D. platyceps there is an additional feature in that the basal 

 fang is seemingly divided into a larger lower, and a much smaller, upper 

 portion (pi. 55, fig. 3). 



Eight species of Dasybranchus may be recognized but some are poorly 

 and incompletely known. Five have been described or reported from the 

 Western Hemisphere; they include D. caducus (Grube) from the West 

 Indies (see Monro, 1933, p. 1059) and western Mexico (Rioja, 1941, 

 p. 730), D. glabrus J D. lumbricoideSj D. lunulatus and D. rectus Tread- 

 well (1901, p. 207) from the West Indies (see below). The last named 

 is incompletely known ; even its generic status must be regarded doubtful 

 for it has since been redesignated Scyphoproctus (Treadwell, 1939, 



