MORPHOLOGICAL PART. 73 



nidse^ and in a few of the later Fistulata, all five radials are in contact 

 laterally. 



The radials, both among each other and with the basals, are united by 

 close suture, the apposed faces being generally smooth, but occasionally 

 wrinkled or striated. 



D. The Anns and Pinnules. 



Admitting that the arms begin with the first plate above the radials, all 

 plates of the rays, from the second one up, are brachials. As before stated, 

 we adopt the terms costals, distichals, and palmars, for the first, second, and 

 third order of brachials, respectively^ When there are further divisions in 

 the rays, the plates are designated as postpalmars, or, when greater detail is 

 required, as brachials of the fourth, or fifth, order, and so on. We also dis- 

 criminate between fixed and free brachials, meaning by "fixed" that the 

 plates so designated take part in the formation of the calyx, and by "free" 

 that they do not.* 



* This is a slight modification of the plan proposed by Carpenter, who reserved the term "free hra- 

 chials " for the plates of the terminal branches alone. He also differed from us in calling the postpalmars, 

 when there are more than four bifurcations to the ray, ''postpalmars of the first, second, or third order." 



10 



