Vlll PREFACE. 



and from nature; of the Echinoderms, from nature, 

 Agassiz, and Miiller; of the Acalephs, from Agassiz; 

 of the Polyps, from Dana, Milne-Edwards, Verrill, 

 and from nature ; and of the Protozoans, mainly from 

 Ehrenberg and Huxley. 



Both this volume, and the "Elements of Zoology" 

 already announced by Messrs. Scribner & Co., and 

 which will combine the study of the Anatomy and 

 Physiology of Animals with that of Descriptive Zo- 

 ology, are intended to precede the Manual mentioned 

 above. 



VASSAB COLLEGE, POUGHKEEPSIE, N. Y., 

 August, 1866. 



