Ill. 
COTTOIDS OF NORTH AMERICA. 
CONTENTS. 
PREFACE 
CHAPTER I. 
ON THE FRESH WATER COTTOIDS IN GENERAL. 
§ 1. Zoological considerations 
§ 2. Genealogy of the Cottoids 
§ 8. Geographical distribution 
§ 4. Habits, food, and use 
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§ 9. 
CHAPTER II. 
ANATOMICAL OBSERVATIONS. 
. General remarks 
. The bony frame of Cottus viscosus 
Comparisons between the skulls of different Cotti 
. Comparative osteology of C. viscosus and A. vih rgintanus 
The bony frame of Triglopsis Thompsonii 
Triglopsis Thompsonii compared with Cottus viscosus and with Acanthocottus virginianus 
- The encephala of Cottus viscosus, C. gracilis, C. gobioides, Triglopsis Thompsonii, Acantho- 
cottus virginianus, and A. variabilis, compared 
. The muscular system of Cottus viscosus 
The skin and the lateral line in Cottoids 
§ 10. The alimentary canal, urinary bladder and ovaries, in Ghitcids 
§ 11. Respiratory apparatus 
cap 
§ 2. 
§ 3. 
CHAPTER III. 
ON THE GENUS CoTTUS, Artedi. 
Zoological characters 
Synoptical table of the species 
Chronological summary of the history of American Cotti 
Species with four soft rays to the ventrals 
I. Cottus Richardsonii 
IL. Cottus cognatus 
III. Cottus Wilsonii 
IV. Cottus Bairdii 
V. Cottus Alvordii 
VI. Cottus meridionalis 
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