III. 



COTTOIDS OF NORTH AMERICA. 



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CONTENTS, 



Preface 



CHAPTER I. 



ON THE FRESH WATER COTTOIDS IN GENERAL. 



1. Zoological considerations 



2. Genealogy of the Cottoids 



3. Geographical distribution 



4. Habits, food, and use 



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CHAPTER II. 



ANATOMICAL OBSERVATIONS. 



§ 1. General remarks ..... 



§ 2. The bony frame of Cottus viscosus . 



§ 3. Comparisons between the skulls of diiferent Cotti 



§ 4. Comparative osteology of 6*. viscosus and A. virghiianm 



§ 5. The bony frame of Trujhpsis Thomjisonii . 



§ C. Trlghpsis Thompsonii compared with Co«ms viscosus and with Acanthocot/us virginiamis 



§ 7. The encephala of Cottus viscosus, C. gracilis, O. gohioides, Triglopsis Thompsonii, Acantho- 



cottus virginianus, and A. variabilis, compared 

 § 8. The muscular system of Cottus viscosus 

 § 9. The skin and the lateral line in Cottoids 



§ 10. The alimentary canal, urinary bladder and ovaries, in Cottoids 

 § 11. Respiratory apparatus . . . . • 



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CHAPTER III. 



ON THE GENUS COTTUS, Artcdi. 



i 1. Zoological characters 



Synoptical table of the species 

 ) 2. Chronological summary of the history of American 

 j 3. Species with four soft rays to the ventrals . 



I. Cottus Richardsonii 

 II. Cottus cognatus 



III. Cottus Wilsonii 



IV. Cottus Bairdii 

 V. Cottus Alvordii 



VI. Cottus meridionalis 



Cotti 



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