CORALS AND CORAL MALCERS. 63 



a fourth of an inch in breadth ; while the fan often grows to 

 a height and breadth of a yard. 



Other species of the Gorgonia family are like clusters of 

 slender twigs, and others like many-branched shrubs or minia- 

 ture trees. 



The exterior of the stem or branch in a Gorgonia is a 

 layer of united polpys, with minute calcareous spicules dis- 

 tributed through the tissues and giving the layer some firm- 

 ness. It is like a bark to the axis of the stem or branch, and 

 may be peeled off without difficulty, and hence is often called 

 the cortex. The outer surface of the dried cortex is often 

 smooth, or nearly so ; but sometimes covered with small pro- 

 minences. Over it there may be seen numerous oblong points 

 (one to each of the prominences if there are any) ; each of 

 these is the spot where a polyp opened out its tentacles when 

 the zoophyte was alive. 



SPICULES OF GORGONI/E, MUCH ENLARGED. 



Kolliker and others have shown that genera, and sometimes 

 species, of the Gorgonacea, may be distinguished by the forms 

 of the calcareous spicules. Some of these knobby spicules 

 are represented in the annexed cut, from figures published by 

 Professor Verrill. The most common forms are those of 

 figures i, 4, 5 ; they occur, with small differences, in the 

 genera Gorgonia, Eugorgia, Leptogorgia, etc. Figure i is from 

 the Leptogorgia eximia V. Figure 2, in which one side is 

 smooth (from the Gorgonia quercifolia V), is characteristic of 

 the genus Gorgonia, but occurs in the species along with 

 forms much like figure i. The forms represented in figures 



