602 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
(20m ?) cilia, and a posterior double row of unequal cilia 
as in the Syllid larvae described above. Of the latter 
row, those cilia which are directed forwards are about 
SO in length, and those which project backwards are 
much shorter (3047). The length of the larva (which still 
shows the seven primary intertrochal segments only) at 
the beginning of the nectochaeta stage is about 700; its 
breadth (exclusive of the appendages) is 2304. The first 
segment bears uniramous parapodia; the remaining six 
all show well-marked neuropodia and notopodia, each 
with a tuft of capillary setae, some of which are smooth, 
others frilled (see Pl. III., fig. 11a). 
The posterior unsegmented region is longer in this 
stage, and bears a telotroch of 80m cilia. <A short median 
caudal appendage, transversely constricted in the middle, 
is present. The walls of the oesophagus are greatly 
thickened in this larva, and still stain very deeply. 
A pair of almost black eyespots—purplish by strong 
transmitted h¢ht—is present on the dorsal surface of the 
head; and immediately behind them a conspicuous coiled 
tube is visible in living specimens. The mouth is small 
and inconspicuous; it is surrounded by a very narrow 
tract of 10m cilia. A few cilia 154 long are usually, 
but apparently not always, present at the base of the 
neuropodium, between this and the notopodium on every 
segment except, probably, the first two. Reddish-brown 
pigment is present on the ventral surface of the pros- 
tomium and on the anal segment; also, in a more diffuse 
form, on the intertrochal segments. The gut contains 
bright yellow globules, but is chiefly coloured by a bright 
blue pigment that is more intense at either end than in 
the middle of the body. 
The oldest larva obtained is of about the same width 
as the last, but has increased in length to 800z, and shows 
