ADVERTISEMENT. 



The increasing professional avocations of my friend Mr. W. 

 White Cooper having prevented his rendering the kind aid 

 which led to the publication of the " Lectures on the Inverte- 

 brata" so speedily after their delivery, a longer delay has oc- 

 curred in the preparation for the press of those on the Ver- 

 tebrate Animals than was originally contemplated. Such notes 

 of these Lectures as Mr. Cooper had leisure to take he has 

 kindly placed at my disposal, and they have served to recal 

 characteristic expressions and ideas which suggested themselves 

 in the course of the oral demonstrations. The desire to verify 

 some of the propositions then enunciated, by repeating the ob- 

 servations on which they were founded, has led to many new 

 dissections and examinations of numerous specimens, and re- 

 ference is made to all those that form part of the Hunterian 

 Museum. I have, also, reconsulted most of the original 

 authorities from which the great bulk of the information im- 

 parted in the Lecture-room had been derived : and a list is 

 n;iven of the Works referred to in the text. 



The utility of the present Volume has been further regarded, 

 by ingrafting into the text some remai'kable discoveries with 



