206 HIROSHI OHSHIMA 
The length, as roughly measured, is about 254. Much weaker 
cilia are found uniformly covering both the parts anterior to 
the first ciliary band and that posterior to the third. The areas 
lying between the bands seem to be devoid of them. 
In C. planei the ciliary bands present are four (K owalew- 
sky) or very rarely five (Selenka) in number, besides the 
uniform ciliation all over the pre-oral hood and anal field. After 
the appearance of pedicels and tentacles these uniform weaker 
cilia disappear (Selenka, 45, p. 172). Mortensen (88, 
pp. 238-4; Pl. i, fig. 8, a, b, c) could not ascertain the presence 
of ciliary bands in preserved specimens of doliolaria which are 
about 1 mm. long, of a light reddish colour, and which were 
found in the Southern Kattegat. He referred them to Psolus 
phantapus and suspected the presence of three ciliary 
bands. Iam much inclined to believe that there are four bands 
running along the circular spaces free from calcareous bodies 
(fig. 8, c). In C. frondosa we have no record of ciliary 
bands (Danielssen and Koren, 11; Des Arts, 2), 
and in C. kirchsbergii the bands seem to be really absent 
(Kowalewsky, 17).  Doliolariae of C. saxicola and 
C.normanziare ciliated uniformly all over as in other stages, 
no segregation of cilia into bands being found (Newth, 86). 
The larva of Phyllophorus urna, too, shows no zonary 
distribution of ciha while actively swimming inside the mother’s 
body-cavity (Kowalewsky, 1%, p. 7). 
When examined in section, the cilia are very obscure and 
markedly short, due to shrmkage. The ectoderm is thickened 
at the band, bemg about twice as thick as other parts, and of 
a lens shape in transverse section (Pl. 9, fig. 25, c,-,). The nuclei 
are situated near the base of the cells. As to these cells I could 
find no distinction between ‘ Wimperzellen’ and ‘ Reserve- 
zellen’ as Reimers (48, 1912, p. 270) did in his observations on 
the larva of Labidoplax digitata. Further, I could not 
clearly make out either ‘ Binnenfaser’ or ‘ Basalstibchen’ as 
clearly figured by him (PI. u, figs. 5-9). 
Hydrocoele.—tThe lobe no. 6 of the hydrocoele, as 
numbered from the dorsal one towards the ventrum, stretches 
