4 1 6 STUDIES FOR STUDENTS 



clustered and fused elements that its heterocercy is scarcely 

 apparent. In short, the most widely modified conditions can be 

 shown to exist in Teleosts in almost every structural character, 

 as in gills, teeth, opercula, circulatory and urogenital organs, 

 sensory structures and nervous system. They have evidently 

 been competing keenly in the struggle for survival, for in every 

 detail of form or structure the most varied conditions exist. In 

 addition to these structural adaptations of the Teleosts, changes 

 in coloration have been rendered possible by the transparency 

 of their scales ; and in their different families these changes 

 have taken place often with striking results." It is impossible 

 to go into the forms of the Teleocephali, for they are so many 

 and varied that there is no outline even, that the limits of the 

 purpose of this paper would permit. A study of the fossil 

 Teleosts would be practically a study of the osteology of the 

 recent forms. 



REFERENCES : 



Dean, Bashford, Fishes Living and Fossil. Macmillan & Co., 1895. Besides 

 the subject-matter this book contains an excellent bibliography of the most valuable 

 works on fishes. 



Zittel, Karl von, Handbuch der Paleontologie, Paleozoologie. Ill Bd. 



Newberry, J. S., Paleozoic Fishes of North America. Monograph XVI of the 

 U. S. Geol. Survey, 4to, 340 pp., 53 pis. 



Woodward, A. Smith, Catalogue of Fossil Fishes of the British Museum. 

 Vols. I, II, III, 1889-1895, London. 



Gill, Theo., Fishes: Standard Natural History. Boston, 1895. 



E. C. Case. 



