REMARKABLE SUBSCRIPTION. 539 



costing one hundred and twenty dollars ! It 

 places in my hands the means of doing hence- 

 forth for Natural History what I had never 

 dreamed of before." . . . 



This work, as originally planned, was never 

 completed. It was cut short by ill-health and 

 by the pressure of engagements arising from 

 the rapid development of the great Museum, 

 which finally became, as will be seen, the ab- 

 sorbing interest of his life. As it stands, the 

 " Contributions to the Natural History of the 

 United States " consists of four large quarto 

 volumes. The first two are divided into three 

 parts, namely : 1st. An Essay on Classifica- 

 tion. 2d. The North American Testudinata. 

 3d. The Embryology of the Turtle, the lat- 

 ter two being illustrated by thirty-four plates. 

 The third and fourth volumes are devoted to 

 the Radiata, and consist of five parts, namely : 

 1st. Acalephs in general. 2d. Ctenophorae. 

 3d. Discophorae. 4th. Hydroida. 5th. Ho- 

 mologies of the Radiates, illustrated by 

 forty-six plates. 1 



1 The plates are of rare accuracy and beauty, and were 

 chiefly drawn by A. Sonrel, though many of the microscopic 

 drawings were made by Professor H. J. Clark, who was at 

 that time Agassiz's private assistant. For details respecting 

 Professor Clark's share in this work, and also concerning the 

 aid of various kinds furnished to the author during its prep- 



