390 EXPLOEATIONS ACROSS THE GREAT BASIN OF UTAH. 



preoperculum, and by the absence of the teeth at the anterior extremity of the tongvie ; 

 the whole margin of the tong-ue in the lattei' genus being provided with a band of 

 viUiform teeth, and the spur-formed teeth of the inferior margin of the preopercuhmi 

 caUing to mind the genus Plcctropoma of Cuvier funong the Serrani. The diiference 

 between the last-named genus, or at least some of its species, and Serramis is indeed 

 not of as great value as that between Labrdx and Itoccus. The only constant charac- 

 ter between Serramis and Pledropoma, as those genera were established by Cuvier, is 

 the spm'-like armature of the inferior border of the preoperculum, while Lahrax and 

 Roccus are distinguished, not only by an equally great and constant difference of the 

 preopercular border, but also by the difference of the lingual dentition. As the former 

 character is of as great value in the Lahraces as in the Serrani, consistency will require 

 that if Plectropoma and Serramis are considered as distinct genera, Roccus and Lahrax 

 should also be so regai'ded. 



The difference between Roccus and Morone is of even more importance than that 

 of Roccus and Lahrax. The distinguishing characters will be referred to under the 

 diagnosis of Morone. 



The name which has been adopted for this genus is one given by Dr. Mitchill, in 

 the year 1814, to a medley com^jrising the Roccus I'meatus (which he called Roccus 

 striatus) and the Otolitlms regalia (which Avas designated as Roccus comes). The name 

 was solely the result of ignorance, on the part of the author, of the application of the 

 ordinary terms used by naturalists at that day. 



As the work in which the name of Roccus was first published is very rare and 

 inaccessible, the remarks of Mitchill on his Roccus striatus have been extracted to show 

 the character of the work. We are indebted to Mr. Brevoort for the loan of the vol- 

 ume.* 



"It has seemed to me proper to make a new genus for this fish and his cono-eners. 

 He has been supposed by some to be the Perca nohilis,\ but the position of his ventral 

 fins forbids him to be considered as a Perca at all. Besides, if he was a member of the 

 Perca family, the specific character of 'eight brown bands' is totally different from the 

 longitudinal stripes that distinguish him, and would rank him among the undescribed 

 species. Besides, he has twO" dorsal fins, while the P. nohiUs has but one." 



In the first place, the so-called Roccus striatus does not differ from the very com- 

 mon European Perch, and from the numerous allied species and genera, in the posi- 

 tion of the ventrals. 



In the next instance, even if it did so differ, Mitchill had, on a previous page, 

 founded a genus for the same reason as in the case of Roccus, and he has given no 

 indications whatever as to how the two are to be generically distinguished. 



The two species that are referred to Roccus belong to totally distinct families. 



Finally, the "Roccus striatus'' had been indicated previously in four different works. 



The name Roccus is itself a barbarous latinization of the popular name "Eock- 

 fish", or simply "Rock", by which its chi ef species is known in some parts of the United 



* Report, in part, of Samuel L. Mitchill, M. D., Prof, of Natural History, &c., ou the Pishes of New York. New 

 York : printed by D. Carlisle, No. 301 Broadway, January 1, 1814. 16mo, 28 p.iges. 



t It is not in any way related to the Perca nobilis. According to Cuvier and Valenciennes, that species is the 

 Chcetodon octofasciatus of Bloch. 



