X PREFACE. 



details,) to M. Latreille, who will himself ex- 

 plain every thing peculiar to his own researches, 



" On the zoophytes, the final division of the 

 animal kingdom, I have availed myself of the 

 labours of M. de Lamarck, respecting the echi^ 

 nodermata, and of M. Rudolphi's work on in- 

 testinal worms, entitled Entozoa. I have, how- 

 ever, carefully anatomized all the genera, and 

 fixed some that were hitherto unsettled. The 

 corals and the infusoria presenting but few 

 facilities for anatomical investigation, I have 

 sketched but briefly." 



But to return to the subject of the present 

 undertaking. Criticism, to be indulgent must 

 cease to be just : it is in vain, therefore, to de- 

 precate its censures, or to appeal to the motives 

 which induced the work as an excuse for its 

 malperformance. 



Still, however, there are points in a work of 

 this nature, on which persons of sound principles 

 in general, and the guardians of the opening 

 minds of others in particular, may demand early 

 satisfaction, and to which, therefore, we shall 

 advert. 



Natural history sometimes involves details 

 which if needlessly dwelt on, might prove of- 

 fensive to delicacy, such unnecessary dilatations 

 have been scrupulously avoided in the following 



