Anatomy of Gorgonid^. 



131 



polyps, as has been said, opens in man}- cases directly into 

 the primary canals. Often, however, the connection between 

 the two is effected by means of secondary canals. 



The Capillaries are well exhibited in this species. Under a 

 low power of the microscope they appear as rows of gran- 

 ules and are doubtless the homologues of the " petits conduits" 

 described by Pouchet and Myevre, and admirably illustrated in 

 PI. IV, fig. I, of their work.' A higher magnifjang power 

 reveals the fact that these cells constitute conjointly very fine, 

 transparent tubes which ramify throughout the coenenchyma 

 and tap the secondary, and perhaps the primary canals, at 

 numerous points. 



In the region between the primary canals and the invest- 

 ment of the axis cylinder, these capillaries are particularly 

 numerous, and appear to be generally parallel to each other 

 and to the axis cylinder. In a transverse section of a branch, 

 the capillaries around the axis will be seen in cross section. 

 The walls in alcoholic specimens seem to be collapsed so that 

 no central space can be detected. In this inner part of the 

 coenenchyma nearest the axis, the peculiar abundance of capil- 

 laries is significant, when we consider the great amount of 

 physiological activity probably involved in the secretion of the 

 axis cylinder. In some cases the capillaries can be traced 

 from their origin in the walls of primary canals to the invest- 

 ment of the axis cylinder. 



In parts of the coenenchyma remote from the axis, the 

 capillaries penetrate and anastomose in ever}^ direction. Thev 

 seem quite numerous near the exterior ectodermal investment. 



Axis Cylinder. In this species the axis cylinder seems 

 to be composed almost entirely of horny matter without the 

 semi-calcareous cylinder found in Plexaiirella dicJwtoma. The 

 entire axis in the present species is probably homologous with 

 the horny core or medullary portion of the axis of P. dicJwt- 

 oma. It presents the same appearance of having been built 



I Contribution a I'Anatomie des Alcjonaires, Published in "Journal de 

 r Anatomic et de la Physiologic." No. de mai, 1870. 



