610 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
The dorsal and ventral rami of the parapodia increase 
in size, whilst the pigment spots between them decrease. 
When about thirty segments have appeared, the para- 
podial rami of segments 7-11 (inclusive) rapidly lengthen 
till they become 200 long, those of the other segments 
retaining a length of about 100”; the former are now 
shaped like a long-handled club, attached by the thick » 
end (Pl. II., fig. 26, shows one of these parapodia from a 
still more advanced worm); the latter lack the “ handle,” 
and are simply pear-shaped. 
In this connection it may be noted that the correla- 
tion between the development of any particular organ and 
the number of segments then present is remarkably small, 
and Claparede figures a forty-seement specimen with 
uniform appendages. When about forty segments have 
been formed the Port Erin larvae are found to have 
developed a pair of large tentacles that project con- 
spicuously from the sides of the head; between them the 
dorsal surface is compressed laterally so as to give the 
head a crested appearance. All cilia disappear from the 
larva, with the exception of some situated in a pit on the 
ventral side of the second segment, and a row placed 
obliquely on each side of the median dorsal crest of the 
head. 
Further specialisation of the appendages takes place. 
The first segment (Pl. II., fig. 23) bears on each side as 
before a bunch of much longer setae than the following 
segments; immediately behind these setae, and apparently 
belonging to the same segment, is a short (40) noto- 
podial projection, below which is a small (30 diameter) 
spherical protuberance, which during life bears straight 
delicate (sensory ?) processes; and immediately behind 
this protuberance is situated a tuft of short (8001) setae, 
and a long (130”) neuropodial projection. The second 
