III. 
DIAGNOSIS 
OF THE 
GENERA AND SPECIES 
CONTAINED IN THIS 
MONOGRAPH. 
COTTUWS, Artedii—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 Wilsonii, 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 Bairdii, Grd.—Body fusiform. First 
dorsal fin very low. ‘Tip of pectorals extending he- 
COTTOIDS OF NORTH AMERICA. 
69 
DIAGNOSIS 
GENERUM ET SPECIERUM 
IN HOC 
MONOGRAPHO 
DESCRIPTORUM. 
COTTUS, Artedi—Capitis superficie leyi; 
spina parva ex capitis latere utroque, interdum al- 
tera aliquanto minore, infra posita, et nonnunquam 
tertia magnitudine sequali secundee. Pinna dorsali 
prima breyiore secunda&. Dentibus palatinis nullis, 
vel eorum rudimentis tantum. Oris fissura ultra 
orbitas non porrecté. Radiis branchiostegis sex. 
I. Pinnarum ventralium radiis, quinque. 
Cottus cognatus, Rich.—Corpore fusi- 
forme. Origine pinne analis ex adyerso sexto 
secundee pinnz dorsalis radio. Pinnis ventralibus 
capite longitudine eequalibus. Ano propius rostrum 
quam pinnee caudalis basim posito. 
Cottus Richardsonii, Agass.—Corpore 
fusiforme. Origine pinnz analis ex adverso tertio 
secundze pinnee dorsalis radio. 
capite brevioribus. 
Pinnis pectoralibus 
Ano medio inter rostrum et 
pinne caudalis extremitatem. Pinnis ventralibus 
ante dorsalem anteriorem et prope inferiorem pecto- 
ralium marginem, insertis. 
Cottus Wilsonii, (rd.—Corpore fusiforme. 
Superioribus pinnarum pectoralium radiis divisis, 
eorumque extremitate ad anteriorem pinne dorsalis 
Pinnis ventralibus 
sub pectoralium medio et ante dorsalem anteriorem, 
secundze marginem porrecta. 
insertis. 
Cottus Bairdii, Grd—Corpore fusiforme. 
Pinna dorsali primé admodum breyi. Extremitati- 
