Anatomy of Gorgonid^e. 123 



tip and carefully examining the axis as its recedes from this 

 point, we can get a presumably fair idea of the process of 

 development in its successive stages in time, as this point is 

 the newest or youngest part of the structure under consider- 

 ation. For some little distance back from the terminal knob 

 the axis seems entirely homogeneous and presents an even 

 surface. Still further back slight wrinkles or longitudinal 

 furrows appear on the surface. These deepen, become more 

 pronounced and increase in number as we trace them back- 

 ward, and soon we see that there are small deposits of lime in 

 the bottoms of these furrows, appearing as wavy white lines 

 on the dark brown surface of the homogeneous horny core. 

 These deposits increase in size as we go still further back- 

 ward until we recognize the well defined vermiform calcareous 

 bodies heretofore described. 



In other species I have demonstrated to my own satisfaction 

 at least, that tiie iiorny core is invested by a layer of endo- 

 thelial cells which presumably secrete the core. As these ver- 

 miform bodies seem to be deposited outside of this axis and its 

 investment, I conclude that they are mesodermal in origin. 

 The fact that the deposit proceeds from the bottom, or inside 

 of these furrows outward in successive stuata, as appears likely 

 from examination of fig. 10, PI. II, is in accord with this 

 theory, h. still more significant consideration is the fact that 

 the mesoderm is the universally acknowledged seat of enor- 

 mous deposits of lime in the form of calcareous spicules. The 

 profound homology indicated on page 108, is another a priori 

 reason for expecting that the calcareous vermiform bodies are 

 mesodermal in origin. 



The calcareous nature of these bodies was demonstrated by 

 their being dissolved out of the fibrous matrix by the action 

 of acids. 



MURICEAi SP. 



ZoANTHODEME profuscly branching, the branches again 



1 Identified from Kent's description in "On Calcareous Spicula of Gor- 

 gonacese," p. 84. 



