have been inserted in their proper places, and two 

 longer pieces, one forming a foot-note near the close of 

 Chap. XI. (p. 119), the other at the end of Chap. XII. 

 (pp. 135-140), describing the probable mode of evolu- 

 tion of the Ehizocephala from the Cirripedia. 



Of the execution of the translation I will say but 

 little. My chief object in this, as in other cases, has 

 been to furnish, as nearly as possible, a literal version 

 of the original, regarding mere elegance of expression 

 as of secondary importance in a scientific work. As 

 much of Dr. Miiller's German does not submit itself to 

 such treatment very readily, I must beg his and the 

 reader's indulgence for any imperfections arising from 

 this cause. 



W. S. D. 



LONDON, 15th Feb., 1869. 



