173 
in the mesenteries B and b clearly shows that we have to do with 
the arrangement MbmB. Thus the diagnosis of Cerianthus, given 
by myself 1912, will have to be somewhat altered as to the arrange¬ 
ment of quartettes. 
The off-shoots of the mesogloea in the proximal part of the 
actinopharynx were very well developed. The ciliated streak on the 
exocoelar side of hyposulcus and hemisulcus was very distinet, as 
shown by fig. 3. (Fig. 3. Transverse section of a part of hyposul¬ 
cus with a directive mesentery (dm), hy\ hyposulcus, cs: ciliated 
streak). 
In the tubes of this species very commonly are found spec- 
imens of Phoronis australis Haswell. (Cf. Iwaji Ikeda: On the 
occurrence of Phoronis australis Haswell near Misaki. Annot. Zool. 
Japon. IV. 1903; p. 115). 
2 . Cenanthus japonicus n. sp. 
Diagnosis: A rather small species. Marginal tentacles about 
65 in number, arranged 2 (dt) 321 j 3231 | 3231 | . Arrange¬ 
ment of the labial tentacles 2 (dt) 413 | 4232 | 4312 | . Longi¬ 
tudinal muscles of the column comparatively weak. Four mesenteries 
attached to the rather narrow siphonoglyph. Hyposulcus rather well 
developed, hemisulci long. Directive mesenteries short, P 2 fertile, 
very long, extending to the aboral pole with a very long ciliated 
tract and a very short cnidoglandular tract. Craspedonemes of the 
ciliated tract few, scattered except in the most proximal part, where 
they are more numerous. P 3 shorter than Mi but somewhat longer 
than Bl, of the same structure as B and b. Arrangement of the 
metamesenteries MBmb distinetly in quartettes. Metamesenteries 
|M and m fertile, rather short, about half as long as the body, with 
very long ciliated tract and short cnidoglandular tract. Their cras¬ 
pedonemes as a rule only in the proximal part of the ciliated tract, 
not forming distinet bunches. Metamesenteries B and b sterile, 
their ciliated tract and cnidoglandular tract of about equal length. 
Their craspedonemes, situated in the aboral part of the ciliated 
tract, scattered, not forming distinet bunches. Quartettes dimin- 
ishing towards the multiplication chamber (without breaks?). Struc¬ 
ture of ciliated tract in the upper part of p 2 , M and m according 
!to type 2, in ps B and b according to type 3. 
