PERCOIDEjE. 25 



lie had received from various parts of North America to a species which he desig- 

 nated vulgaris, and our Lake Huron ones were examined among the rest and 

 returned to us under that appellation. As has been mentioned, however, in the 

 preceding pages, M. Valenciennes found it necessary, on receiving an additional 

 number of good examples from different localities, to distribute them into several 

 species, and to revise the characters of the genus Pomotis, of Centrarchus, so closely 

 allied to it, and to constitute an intermediate genus, which he named Bryttus- 

 He says, " Les pomotis seront ceux des poissons de ce groupe qui auront quelques 

 dentelures plus ou moins marquees au bord du preopercule, les palatins et la langue 

 lisses et sans dents. lis nont de dents que sur le chevron du vomer. Le nombre 

 des rayons cpineux de Fanale ne sera plus quun caractere secondaire ; car nous 

 avons deja parle d'un pomotis qui a quatre epines a cette nageoire." The den- 

 tition furnishes, in fact, the only means pointed out of distinguishing these three 

 genera *, for we have already seen that our specimen of the Centrarchus oeneus has 

 its preoperculum as conspicuously denticulated as the Pomotis vulgaris figured in 

 the Histoire des Poissons, though the latter is described by the Baron as displaying 

 this character more distinctly than its congeners. On the other hand, the pomotis 

 described below, has the denticulations very slight indeed, and in one specimen 

 scarcely perceptible. Our Lake Huron examples also want the crenatures of the 

 upper humeral bone, represented in the Histoire des Poissons (t. xlix.) ; their 

 bodies are more nearly orbicular in profile, the greatest depth equalling the distance 

 between the preoperculum and the posterior part of the dorsal and anal fins ; the 

 ventrals are under the third or fourth dorsal spine, while in the figure referred to 

 they are opposite to the first spine of the dorsal, and the numbers of the scales 

 differ as well as the rays of the fins. These discrepancies were perhaps sufficient to 

 have authorised me to give a new specific name to the Lake Huron fish which 

 appears to be the most northern of the genus, but our figure was engraved previous 

 to the publication of M. Valenciennes' revision of the genus under the name by 

 which Cuvier had himself labelled the specimen, and I have therefore, for the 

 present, continued to it the appellation of vulgaris. Correct and minute descrip- 

 tions of recent specimens are particularly necessary to complete our knowledge of 

 this group of Percoidece, owing to the rapidity with which the fish composing it 

 lose their brilliant colours after death. M. Valenciennes describes his P. vulgaris 

 as having no coloured streaks on the cheeks, and this, if there be no mistake, 



* In the operculum ending by two points, and in the smallness of the suboperculum, C. ceneus differs remarkably from 

 our P. vulgaris, whose operculum ends in a round lobe, and the suboperculum is prolonged so as to form the under margin 

 of the gili-cover. We do not know how far these characters prevail in other species. 



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