114 Natural History Bulletin. 



trading when a single branch is touched. The individual 

 polyp is darker in color than the branches. It does not pro- 

 trude so far from the general surface as in Briaremn. 



The tcniaclcs are very short and blunt, and the tentacular 

 papillfce are reduced to mere warty protuberances, each of 

 which is mobile and contractile. The surfaces of tentacles 

 and papillae are covered with vibratile cilia. 



hs\ examination of PI. II, fig. 2, will show the appearance 

 of a polyp viewed from above. It will be seen that these ten- 

 tacles can hardly be of much service in conveying food to the 

 mouth except by means of cilia. In the figure the mesen- 

 teries and body wall appear as light markings showing 

 through the oral surface of the polyp. 



A side view of an expanded polyp will reveal deep furrows 

 or longitudinal plaitings in the body wall extending down from 

 the points of juncture of the adjacent tentacles. It seems 

 likely that the polyp in retracting, throws the body wall into 

 a series of longitudinal folds and thus lessens its " calibre," as 

 it were. 



In retraction, the polyps do not appear to withdraw so far 

 within the calicle as in Briarcuni. 



The gullet does not occupy so great a portion of the calicu- 

 lar space as in most other species examined. Its histological 

 characters could not be satisfactorily ascertained. It is a 

 nearly straight tube when the polyp is expanded and is 

 thrown into convolutions Vkhen retracted. 



The mesenteries are long and their attachments to the calicle 

 occupy meridional lines on the internal surface of the latter. 

 They are much longer in proportion to the size of the polyps and 

 diameter of caHcles than those of any other species examined. 

 The histological features of the mesenteries and their attached 

 muscles were better shown in sections of this species than in 

 any other. Fig. 6, PI. II, is a representation of a portion of a 

 mesentery with the corresponding part of one of the retractor 

 muscles. The muscle is seen to be a plate (a) of parallel 

 muscle fibres, each fibre containing nuclei irregularly dis- 



