640 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
The extent to which the larval rows of black 
pigment-spots are retained varies considerably in the 
different specimens, they being in some confined to a 
patch on each side of every segment (as in fig. 46), and 
in others quite as fully developed as in the second 
metamorphosis stage described above; pigment-spots are 
now also irregularly scattered over the anterior part of the 
ventral surface, and a very variable number of larger 
(20-50% diameter) patches are present on the dorsal 
surface of the anterior segments. One pair of eye-spots 
may be seen in living specimens. 
There is no longer any trace of the prototroch, 
unless it is represented by two short rows of small cilia 
that are situated one on each side of the head. The short 
straight capillaries of the larva persist as the dorsal 
setae of the tubicolous form; ventral uncini are also 
present. The scapha (Pl. IV., fig. 46; Sc.) bears a single 
median posterior process and a pair of lateral anterior 
ones; it appears to retain a faint trace of the telotroch 
in the form of a girdle of faintly-staining cells near its 
posterior border (PI. IV., fig. 46; Tér.?); the anal ridge 
with its pigment-spots has atrophied. 
The tube (1,200 long) is much longer than the 
worm (8004 long in the fixed condition, the paleae 
projecting to an additional distance of 150); at their 
widest part both worm and tube are 250 broad. The 
walls of the tube are very thin and transparent, and only 
the most minute particles of foreign matter are attached 
to it, and these only in very small quantities. 
The development of Pectinaria has apparently been 
described by Bobretzky (Verh. Ges. d. Naturf. Kiew; Vol. 
VIII.; 1873) but I have not been able to refer to his 
paper. Leschke (1903: p. 127; Pl. VI., fig. 13) also 
briefly describes this and figures an advanced 
Metatrochophore with its lips extended. Claparéde and 
