BRYOZOA. 323 



CHAPTER II. 



CLASSIFICATION AND INTERRELATIONS OF FAMILIES 



AND GENERA. 



As thjs work deals solely with Palaeozoic Brjozoa it is quite 

 unnecessary to enter into the various systems of classification 

 that have been proposed for the arrangement of Secondary, 

 Tertiary, and recent representatives of the class, excepting in a 

 general way. and more in detail when these classifications in- 

 cluded some of the Palaeozoic types. 



D'Orbigny's elaborate classification shows a knowledge of 

 bryozoan form that stands unrivaled even to-day. His lucid 

 descriptions and excellent plates reveal a wonderful variety of 

 structure and an almost endless array of beautiful forms. How 

 very unfortunate then that a work so laudible should be ac- 

 companied by an extremely artificial classification, and a 

 nomenclature so complex that it is bewildering. 



D'Orbigny's first attempt at a systematic arrangement is found 

 in his "Cours elementaire de Palaeontologie," which was shortly 

 followed by a more comprehensive synopsis of the fossil forms 

 in the "Prodrome de PalaeoDtologie." Lastly in the ''Palaeon- 

 tologie Francaise, vol. V" he publishes his completed classifica- 

 tion, embracing all the forms known up to 1852, making in all 

 two hundred and nineteen genera and one thousand nine hun- 

 dred and twenty-nine species. Upon this vast array of bryozoan 

 diversity he based a wonderfully artificial system, which has 

 been abandoned, perhaps without an exception, by all subse- 

 quent authors who have made a special study of Bryozoa. His 

 two grand divisions, the BR YOZOAIRES CELLTJLINES and BR YOZOAIRES 

 CENTRIFUGIXES correspond very nearly with Busks CHEILOSTOMATA 



