Anatomy of Gorgonid.-e. 155 



living tissues. I should judge that the two species mentioned 

 were also of more rapid and vigorous growth. 



The spicules are much smaller than in any other species 

 studied. Their size, compared with the others, may be judged 

 by comparing fig. 8, PI. X, with the spicules figured on other 

 plates, all of which were drawn to the same scale. The 

 remaining spicules on this plate are much more highly magni- 

 fied in order to show their characteristics. They are remark- 

 ably uniform in size, or, at least in length, and also in color, 

 being of the same bright yellow as the zoanthodeme to which 

 they, of course, impart their color. 



The most characteristic shape is the one illustrated in figs. 

 10, 13, PI. X, and called "scaphoid" by W. S. Kent. They 

 are unsymmetrical and consist of a somewhat arcuate heavy 

 shaft with four series of compound tubercles surrounding it on 

 its concave and two adjoining sides, leaving the convex side 

 bare. When viewed from the front these scaphoid spicules 

 present the appearance shown in figs. 9 and 11. This species 

 bears many resemblances to Afun'cea, and among them not 

 the least interesting is the fact that they both possess unsym- 

 metrical spicules, although the patterns are quite different. 



Another form of spicule found in R. jlahcUtiin is the "dumb- 

 bell" illustrated in fig. 14, PI. X, and called by Kent the 

 "Leptogorgian type." 



Kent thinks that there is a correspondence between the size 

 of spicules and the thickness of the coenenchyma in Gorgon- 

 ace^.' This theory is not entirely borne out by the exami- 

 nation of the six species considered in this paper. Bjiareum 

 ashestimim has decidedly the thickest coenenchyma, and 

 Plexaurella dichotoma has the next thickest. As regards the 

 size of spicules, they rank 4th and 3d respectively. The 

 largest spicules found were in Etinicea totirneforti and the 

 next largest in Eunicea muricata. These rank 4th and 3d 

 respectively as regards thickness of coenenchyma. So we find 

 that the rule does not apply in four out of the six species 



1 "On the Calcareous Spicula of the Gorgonacea'," p. 89. 



