79 
of developing in the same way as normal arms. No support for 
the barnacle theory can be derived from the structure and morpho- 
logy of the pinnules, or from the cirri, which are structures of quite 
another morphological value than that of the pinnules. 1 ) 
h A further discussion of these problems is given in the authors „Studies 
in the development of Crinoids“; Papers from the Department of Mar¬ 
ine Biology of the Carnegie Institution of Washington. Vol. XVI. 1920. 
p. 80-82. 
5-6-20. 
