224 TEN years' progress in vertebrate paleontology 



PALEOZOIC FISHES 

 BY BASHFOED DEAN 



CONTENTS p^gg 



Introductory 224 



Discovery of new forms 224 



New localities yielding Paleozoic fishes 224 



The riddles of the relationships of fishes 225 



Introductory 



There are three questions which a summary of the work of the past 

 decade might reasonably answer: 



(1) What new forms have been discovered? 



(2) What new localities have yielded Paleozoic fishes? 



(3) What progress has been made in understanding these fishes them- 



selves, both in structure and relationships? 



Discovery of new Forms 



The past decade has not recorded the discovery of many new and 

 remarkable fishes. We note, however, the description by Traquair of the 

 anomalous Gemundina and Hunsruclcia from the Devonian of Gemiin- 

 den. Unfortunately these forms are not well preserved and it is per- 

 haps profitless to discuss them at the present time. On the other hand, 

 the new Ateleaspis (Traquair) from the Upper Devonian of Scotland is 

 favorably fossilized and is one of the really significant finds of the past 

 decade. Among Placoderms we record the description of Protitanichthys 

 {Coccosteus ?), Dinomylostoma (Eastman), Protosteus, Pachyosteus 

 (Jaekel) among the most important. 



In the subclass of sharks no forms of extraordinary interest have been 

 found. We may mention a new Edestid {Lissoprion Hay) from N'evada 

 and several cestracionts from the middle West (Eastman). 



Dipnoans have been elusive; dental plates of Synthetodus (Eastman) 

 from the Devonian of Iowa belong possibly to this group. 



No Chimaeroids of especial intercrt have been noted. 



Teleostomes have been found in considerable numbers in later Paleo- 

 zoic horizons, but they are lacking in interest from the larger viewpoint. 



New Localities yielding Paleozoic Fishes 



The past decade has witnessed the discovery of new localities in various 

 horizons throughout the world. Among the most important are dis- 



