Anatomy of Gorgonid^. 121 



The cylinder ot semi-calcareous matter which invests the 

 core is composed of two very distinct elements, ist, calcareous 

 matter deposited in the form of vermiform bodies, and 2d, a 

 fibrous, corneous matrix in which what I have called the ver- 

 miform bodies are embedded. The relative proportion of 

 these two elements varies greatly with the size of the entire 

 axis cylinder, the calcareous bodies increasing with the diame- 

 ter of the axis and greatly preponderating over the matrix in 

 the region of the stolon or root-stalk of the zoanthodeme. In 

 this latter region the axis is almost as hard as flint, harder 

 than the corallum of ordinary so-called " hard corals." 



Fig. 9, PI. II, represents a transverse section of the axis 

 cylinder as it appears under a ^ inch objective; a, is the 

 horny core or medulla; b, b, b, are cross sections of the ver- 

 miform bodies; c, is the core of a branch from the main axis 

 cut a short distance above its origin. 



Fig. 8, PI. II, represents a longitudinal section of a part 

 of a vermiform body and its investing matrix. The cal- 

 careous body shows evidence of having been built up by 

 superimposed deposits in the same manner as the core of the 

 cylinder. It seems to be nearly or entirely composed of cal- 

 careous matter. The matrix (fig. 9, a) is plainly fibrous in 

 structure, the fibers being parallel to the long axis of the ver- 

 miform body. 



A transverse section of the vermiform body, highly magni- 

 fied (fig. 10), shows evidence of having been deposited at suc- 

 cessive stages from the inner * to the outer side. The stria- 

 tions give the appearance of stratification, the inner strata 

 being deposited first and the outer last. 



In the fresh specimen a transverse section of the axis will 

 reveal a stellate outline to the cut surface of the semi-calcareous 

 outer cylinder (see fig. 3, f), the points of the star being eight 

 in number and situated between the inner sides of the primary 

 water-vascular canals. 



I The inner side is the one nearest the liorny core of the axis. It is the 

 lower side in the figure. 



