INTRODUCTION. 55 
been very different. The one has left a favorable record 
of himself throughout ; while of the other, only traces 
enough remain, to mark his errors. 
The other principal contributors to the elucidation of 
tins branch of zoology will be named in the general 
remarks on the respective genera, and a particular 
account of their contributions to the history of the genus 
will be given. 
