ii8 Natural History Bulletin. 



the same in all Gorgonid^e, it requires no further mention 

 here. 



Water-vascular System. This is of the typical Gor- 

 gonian character and differs in some respects from that found 

 in Briarcwm. It is practically the same in all genera possess- 

 ing a more or less horny axis cylinder. 



The Primary Water-vascular canals are a system of paral- 

 lel tubes grouped regularly around the axis cylinder (See PI. 

 II, fig. 3, e, e, e). There are eight of these canals shown in 

 a cross section of a branch. They traverse the whole length 

 of each branch in the zoanthodeme from its origin to near the 

 point where the axis cylinder terminates at or near the bottom 

 of one of the terminal calicles. An examination of one of 

 these canals in sections of a fresh specimen will disclose an 

 oval opening having the smaller end of the oval nearest the 

 axis cylinder. The lining of these canals is endothelial and 

 the cells of which it is composed are furnished with large 

 active cilia which are constantly at work pumping water 

 through the canals and their various ramifications. The 

 action of the cilia is continued for some time if the sections 

 are kept in seawater, and the view under the microscope pre- 

 sents a scene of great activity, reminding one of the working 

 of the cilia attached to the gill tentacles of a clam. The cur- 

 rent of water thus produced is strong and constant. 



There is no direct or immediate connection between the 

 body cavities of the individual polyps, except, perhaps, the 

 terminal ones and these canals. That is, the calicles do not 

 open directly into the canals and there is always a considera- 

 ble mass of coenenchyma crowded with spicules between the 

 two. This connection, however, is more or less indirectly 

 effected by means of the 



Secondary Water-vascular can.ils which traverse the coenen- 

 chyma in great numbers, tap the primary canals at irregular 

 but frequent intervals throughout the length of the latter, and 

 wind in tortuous courses among the spicules, anastomosing 

 freely and opening into the gastro-vascular cavities of the 



