612 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
to attain a much greater size. These two larvae appear 
to be considerably older than any described by either 
Claparéde or McIntosh, as these authors make no mention 
of the short curved setae of segments 2-3, which would 
seem to develop some time before the growth of the 
anterior prolongation of the head. 
I have seen nothing, even in the oldest larvae, of the 
two rudimentary cirrus-like outgrowths that occurred 
on each parapodium of the second and third segments in a 
specimen described by Claparéde from Christiansand 
Harbour (1868: p. 79; Pl. VI., figs. 8-9). Probably these 
were, as he suggests, abnormal. 
Spionid B (Pl. III., figs. 35-54) _N ectosoma— 
This larva is characterised by its slenderness, the anterior 
segments of a well-expanded specimen being quite as long 
as they are broad. | 
The youngest specimen examined (800 by 80 z) 
shows ten segments and a posterior unsegmented region ; 
the appendages scarcely project, and the setae, which are 
long and slender, have become so much folded round the 
body in mounting (this larva was not examined alive) as 
to make further observations upon them impossible. The 
head is rounded in front and already bears two pairs of 
eyes, a small pair situated on the dorsal surface not far 
from the middle line, and a larger pair situated at the 
sides of the head or slightly on the ventral surface. Proto- 
troch, telotroch, and intertrochal cilia are present, but 
their extent cannot be determined. Close to the anus 
there is a pair of very characteristic groups of anal styles 
(Pl. III., fig. 34; An. sty.). Later stages show the growth 
of the worm by the addition of further segments; a very 
conspicuous pharynx appears (PI. III., fig. 53; Ph.), the 
tentacles develop, and both notopodia and neuropodia 
begin to project from the sides of the body. A mounted 
