584 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
(1893: p. 279; Pl. XIIT., figs. 16-29), on account of 116 
general form, its polytrochy, the position of its eyespots, 
the condition of its mid-gut, its sickle-shaped bristles, 
and the pigmentation of its anal segment. Of these 
characters the polytrochal condition of this larva appears 
to me to be a secondary specialisation, quite distinct from 
the simple polytrochal condition of ‘‘ Harpochaeta’’, nor 
do any of the characters seem very conclusive. Our form 
is certainly very unlike any other known Syllid larva, 
such as De Saint-Joseph’s, as Hacker himself points out; 
and although “ Harpochaeta”’ may to some slight extent 
help to bridge the gap, the evidence that this larva is a 
Syllid appears to me to be insufficient. 
Potynoip#. (Pl. I., figs. 15-20.) 
There appear to be several species, belonging to one 
or more genera of the Polynoidae, occurring as larvae at 
Port Erin during July. I have not yet been able to go 
fully into the differences between them, but the following 
account refers especially to the commonest of these, and 
with but slight modifications is true of all. 
Trochophore.—tThe Trochophore after fixation 
is usually somewhat longer than it is broad, having a _ 
length of 300” and a breadth of 250; but during life 
it is of a more nearly spherical shape (PI. I., fig. 15). 
The commonest form appears to be of a deep violet colour, 
on account of the pigmentation of the walls of the 
stomach. 
The prototroch consists of three rows of cilia (Pl. L., 
fig. 15, 15a), which are probably carried by three corre- 
sponding rows of cells. The cilia of the most anterior 
row are 1d long, and sections show that this row is 
situated slightly in front of the other two, which arise 
close together, the cilia of one being directed forwards 
