240 M. MIYAJIMA : 



The liypostome (Woodcut 1, I, II, h), the superior prolonga- 

 tion of the disc, is slightly conical, diminishing gradually in 

 its diameter from the base towards the free end where the 

 mouth opens. A little below the mouth the liypostome bears a 

 brush-like group of about 180 filiform tentacles {ot.) which are 

 arranged in three or more closely packed verticils, the outer 

 tentacles being much larger than the inner. The outermost 

 ones attain a length of 00-55 mm., while the innermost are so 

 small and crowded that I could neither measure them well nor 

 count their exact number. Below the oral tentacles the liypo- 

 stome is slightly constricted, but there is no indication of syphono- 

 glypli which is said to be present in the oral tube of Branchio- 

 cerianthus iirceolus. The side of the liypostome turned towards 

 the lower edge of the disc passes gradually to the disc, while 

 on the opposite side it seems abruptly raised from the disc, 

 so as to make an angle between. The liypostome is thus oblique 

 to the disc proper which again is not perpendicular to the axis 

 of the hydrocaulus. Hence we can show the relation of the three 

 parts, the liypostome, the disc and the hydrocaulus, diagram- 

 atically with three lines, of which two vertical ones, correspond- 

 ing to the axes of the liypostome and of the hydrocaulus, meet 

 with an oblique one representing the axis of the disc, forming 

 obtuse angles betw^een them (Woodcut 1, I). 



The base of the hypostome (Woodcut 2, B.) occupies about the 

 middle of the disc, but on the side turned towards the lower edge, 

 its base gradually becoming lower and lower, may be said to 

 stretch as far as the margin of the disc, while laterally and towards 

 the higher edge it is distant from the margin 35 mm. and 22 mm. 

 respectively. It thus assumes an ovoidal outline, the pointed end 

 attaining the lower margin of the disc and passing directly to the 



