1 74 ALLAX HANCOCK PACIFIC EXPEDITIONS VOL. 25 



PLATE 18 



Magelona sacculata, new species (Sta. 2311) 



1. Anterior end in dorsal view showing thorax and four abdominal 

 segments, x 70. 



2. Posterior end showing pygidium with lateral processes and last 

 segments, x 70. 



3. A hooded hook from an abdominal segment, in lateral view, x 1500. 



4. A modified mucronate seta from the ninth segment, x 1500. 



5. An accompanying slender seta from the ninth segment, x 1500. 



6. Cross section of the ninth or modified segment, showing arrange- 

 ment of parapodial lobes and setae, seen from the front, x 260. 



7. Cross section of an abdominal segment, showing the arrangement 

 of parapodial lobes and hooks, seen from the front, x 260. 



