PREFACE. Vll 



of our students the best assistance I could recommend for 

 their studies in this direction. In fulfilment of it I ap- 

 plied to Professor VAN DER HOEVEN for his permission 

 to translate his Work, in which I found all that could 

 be required. He had the kindness not only to grant this 

 permission, but also to enrich the English translation with 

 numerous references to works too recent for notice in his 

 own second edition. It is to be much regretted that his 

 other engagements did not allow him, as I requested, 

 to weave the new matter in his own terse and pleasing 

 style into his introductions to the classes and elsewhere. 

 Consequently such additions, in this respect, as are in- 

 cluded within square brackets are mine. 



The study of Zoology is now in such general favour 

 with cultivated persons in this country, that I believe the 

 present work, from its scientific value and the interest of 

 its historical and other notices, as well as from the con- 

 tinuous references to the works of the original discoverers, 

 will secure for itself, beyond the walls of Universities, a 

 reception not unworthy of its Author's great name. 



W. C. 



CAMBRIDGE, July r, 1856. 



