398 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



families and a number of useless names are invented. The 

 fifth volume of D'Orbigny's Paleontologie Fran$aise (1850-51) 

 enumerates from Cretaceous deposits no less than 1,929 species 

 and 219 genera, and gives a description and illustration for 

 each species. The publications of MacCoy and J. Hall 

 (1851-52) on Palaeozoic Bryozoa, the excellent memoirs of 

 Hagenow (1851) on the Bryozoa of the Maestricht Chalk, 

 and those of Haime (1854) on Jurassic Bryozoa, were but 

 little influenced by D'Orbigny's classification. 



Busk passed from a careful anatomical study of living 

 Bryozoa to the study of fossil forms, and began the 

 publication of a monograph describing the Bryozoa or 

 Polyzoa in the English crag. In this monograph, which was 

 unfortunately never completed, Busk sub-divided the forms 

 possessing calcareous cells into two orders (Cheilostomata 

 and Cyclostomata), these two orders almost coinciding with 

 the two chief orders in D'Orbigny's system. But Busk pro- 

 posed considerable modifications for the minor sub-divisions. 

 For the differentiation of families and genera he used in the 

 first instance the form and arrangement of the "aggregate" or 

 colony, in the next instance the characteristic features of the 

 individual zocecium or cell. 



Great progress has been made by zoologists in the knowledge 

 of the internal structure of the polypides, and of the diverse 

 forms of colonial growth. Van Beneden, Smitt, Nitsche, 

 and Hincks have taken a pre-eminent part in the zoological 

 researches, and the whole group has been admirably reviewed 

 by Ray Lankester in the Encyclopedia Britannica. Stoliczka 

 and Reuss have contributed largely to the knowledge of Tertiary 

 and Mesozoic Bryozoa, while Lonsdale, MacCoy, J. Hall, and 

 E. D. Ulrich have added much valuable information about 

 Palaeozoic types. 



The Palaeozoic Chsetetidae and Monticuliporidae have been 

 made the subject of a voluminous literature; some of the 

 most eminent writers, Milne-Edwards, Haime, Nicholson, 

 and Dybowski, consign these groups to the Corals, whereas 

 Lindstrom, Rominger, and Ulrich place them with the Bryozoas. 



In contrast to most classes of the animal kingdom, fossil 

 remains of Brachiopods were known earlier than the recent 

 forms. Since the beginning of the seventeenth century, 

 Terebratulites or " Conchae anomiae" have played a part 

 in the illustrated works on Natural History. A living 



