Bbnham. — Notes on New Zealand Polvchaeta. 



391 



It occurred to me tliat possibly in the young condition some evidence 

 of the typical serrations and fork might exist ; but the examination of the 

 smallest, and therefore youngest, of the worms (one which measures 14 mm.) 

 shows no trace of any serration. But in the mid-body most of the dorsals 

 do present an obsolescent spur, resembling that of the ventral chaetae of 

 the adult (fig. 10) ; but it is situated rather farther from the apex. In 

 a few this was totally absent ; in a few others — two or three in the bundle 

 — a definite fork is present (fig. 11). 



11 



10 



Fig. 6. — A gill (camera outline, x 10). 



Fig. 7. — One of the chaetae from a dorsal bundle of an adult worm ( x 45). 



Fig. 8. — One of the chaetae from a ventral bundle of an adiilt worm ( X 45). 



Fig. 9. — The tip of a ventral chaeta ( x 180). 



Fig. 10. — A dorsal chaeta from the mid-body of a very young specimen, with a •' step " 



below the apex ( X 45). 

 Fig. 11. — Another dorsal chaeta from the same bundle, showing the bifurcation more 



usually present in the genus, but in this species only occasionally present, 



and only in the young stages ( X 45). 



The origin of the shorter limb of the fork is farther removed from the 

 apex than is the step-like trace of spur in the other chaetae, suggesting 

 that the tips of the latter are worn away, reducing the tip of the main 

 axis as well as the shorter limb of the fork, for these forked chaeta appear 

 to be newly formed young bristles ; but in the adult I see no indication 

 in the interior of the chaetae of any cavity leading into the short spur 



