III. 



COTTOIDS OF NORTH AMERICA. 



G9 



DIAGNOSIS 



GENERA AND SPECIES 



CONTAINED IN THIS 



MONOGRAPH. 



COTTUS, Artedi. Upper surface of head, 

 smooth. One small spine on the side of the head; 

 sometimes a second still smaller below, and occa- 

 sionally a third of the size of the second. First dor- 

 sal fin lower than the second. Palatine teeth none, 

 or rudimentary. Cleft of mouth not extending be- 

 yond the orbits. Six branchiostegal rays. 



I. Rays of ventral fins, five in number. 



CottUS COgnatUS, Rich. Body fusiform. 

 Origin of anal fin opposite to sixth ray of second 

 dorsal. Pectorals equalling the head in length. 

 Anus situated nearer the snout than the base of 

 caudal fin. 



Cottus Richardsonii, Agass. Body fu- 

 siform. Origin of anal fin opposite to third ray of 

 second dorsal. Pectoral fins shorter than the head. 

 Anus situated midway between the snout and tip of 

 caudal fin. Insertion of ventrals in advance of the 

 anterior dorsal, and near the lower edge of pectorals. 



Cottus WilSOnti, Grd. Body fusiform. 

 Upper rays of pectoral fins, branched; their tip 

 reaching the anterior margin of second dorsal fin. 

 Insertion of ventral fins under the middle of pecto- 

 rals, and in advance of the anterior dorsal. 



Cottus llnirtlii, Grd. Body fusiform. First 

 dorsal fin very low. Tip of pectorals extending be- 



DIAGNOSIS 

 GENERUM ET SPECIERUM 



IN HOC 



MONOGRAPHO 



DESCRIPTORUJC. 



COTTUS, Artedi. Capitis supcrficie Icvi; 

 spina parva ex capitis latere utroque, interdum al- 

 tei-a, aliquanto minore, infra posita, et nonnunquam 

 tertia magnitudinc Eequali secundae. Pinna dorsali 

 prima breviore secunda. Dentibus palatinis nullis, 

 vel eorum rudimentis tantum. Oris fissura ultra 

 orbitas non porrecta. Radiis branchiostegis sex. 



I. Pinnarum ventralium radiis, quinque. 



Cotllis C0liatll, Rich. Corpore fusi- 

 forme. Origine pinnae analis ex adverso sexto 

 secundae pinnae dorsalis radio. Pinnis ventralibus 

 capite longitudine sequalibus. Ano propius rostrum 

 quam pinnae caudalis basim posito. 



Cottus Richardsonii, Agass. Corpore 



fusiforme. Origine pinnae analis ex adverso tertio 

 secundse pinna; dorsalis radio. Pinnis pectoralibus 

 capite brevioribus. Ano medio inter rostrum et 

 pinnas caudalis extremitatem. Pinnis ventralibus 

 ante dorsalom antcriorem et propc inferiorem pecto- 

 ralium marginem, insertis. 



CottllS Wilsonii, Grd. Corpore fusiforme. 

 Superioribus pinnarum pectoralium radiis divisis, 

 eorumque extremitate ad anteriorem pinnae dorsalis 

 secundae marginem porrecta. Pinnis ventralibus 

 sub pectoralium medio et ante dorsalem antcriorem, 

 insertis. 



ISairdii. Grd. Corpore fusiforme. 

 Pinna dorsali prima admodum brcvi. Extremitati- 



