166 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 7 



the notopodial fascicles are whorled. (5) Stout falcate hooks (pi. 30, 

 fig. 19) are only in segments 2 and 3. 



The last 20 or more segments are short, crowded. The anus is sub- 

 terminal, bounded along its ventral margin with 3 subequal, clavate 

 cirri, and a median cirrus dorsal to the proximal paired cirri. 



Color in life golden brown with greenish yellow, especially in the 

 anterior dorsal region; posterior region darker. Color in alcohol cream 

 or drab yellow. 



Poecilochaetus johnsoni inhabits long, tortuous burrows, that are 

 surrounded by a loosely constructed covering of rust-colored sand which 

 crumbles readily. The substratum is black, muddy sand that can be 

 walked on without sinking. It is proximal to the open ocean, but cut 

 off by a low sand spit. 



It is a pleasure to dedicate this species to Dr. Martin W. Johnson, 

 of the Scripps Institution of Oceanography at La Jolla, California, who 

 made these collections possible. 



Holotype.— AHF no. 22. 



Distribution. — Mission Bay, southern California, in the low, inter- 

 tidal zone. 



Systematic discussion. — Poecilochaetus johnsoni is distinguishable 

 from other species of this genus as indicated in the key above. It ap- 

 proaches P. tropicus Okuda more nearly than other species in general 

 appearance and parapodial structures. Okuda was unable to attribute 

 long, paired palpi to P. tropicus, but since these structures autotomize 

 readily, they might have been lost from the specimens when examined. 

 The presence or absence of stout, dorsal hooks in the posterior region 

 has not been ascertained for P. tropicus, because of incomplete materials. 

 They are absent in P. johnsoni. Another notable difference between 

 these two is in the shape of the parapodial cirri after the twenty-first 

 segment. In P. tropicus they are slender, cirriform, in P. johnsoni these 

 continue broad, foliose (pi. 30, fig. 14). 



