250 M. MIYAJIMA : 



half of it there are visible from outside 15-20 longitudinal wavy 

 bands (Fig. 17). They stand about 2-3 mm. distant from one 

 another and run down to about the middle part of the hydro- 

 caulus where they become obscure. From the surface they look 

 remarkably like the mesenterial filaments of an Anthozoon. These 

 wavy bands anastomose here and there with one another and 

 give to the hydrocaulus of our specimen an appearance much 

 resembling that of Corymorpha. Though the bands are in the pre- 

 served state still visible, they were more conspicuous when fresh. 

 These longitudinal bands show themselves in cross-section (Fig 18) 

 as dense spots (:r) in the mesoderm, which have a great affinity for 

 any staining agents. From the bad state of preservation of the 

 specimen, in which the ectodermal and endodermal cells were 

 mostly lost, I could not ascertain whether the wavy bands were 

 the endoderm canals, a structure peculiar to Corymorpha^ or not. 

 I think it, however, very probable that they existed, and gave 

 rise to these band-like appearances. In the published accounts 

 of Monocaulus imperator of Allman the endoderm canals were 

 plainly described and figured. 



The mesoderm is very well developed, especially in the 

 hydrocaulus where it reaches a thickness of about 0.2-0.3 mm. 

 This remarkable layer shows itself in the form of a fibrillated 

 membrane, which, wheu macerated with caustic potash, is separated 

 into two layers, the outer longitudinal (Fig. ID, /./.) and the 

 inner circular (Fig. 19, c.L). The former is thicker and stains 

 less with any coloring matter than the latter. 



In our specimen there is no sudden bulb-like expansion at 

 the lower end of the stalk, such as is described by Mark in 

 Branchiocerianthiis urceohis or by Allman in Monocaulus imperator. 

 The lowest and broadest part of the hydrocaulus is enclosed for 



