iv PEEFACE. 



The Memoir on the Embryology of the Starfish, Part I., has been repub- 

 lished substantially as it originally appeared in 1864, in advance of the 

 remainder of the volume. I have added notes in brackets on the points 

 where additions have been made by subsequent investigations for the sake 

 of calling attention to the present condition of| the subject, and I beg the 

 reader to remember that it was written thirteen years ago. 



ALEXANDER AGASSIZ. 



Museum of Comparative Zoology, > 

 Cambridge, April, 1877. | 



