NATURAL SCIENCES OF PHILADELPHIA. 245 



and rather abruptly pointed at the tips. Vomer with teeth like those of the 

 jaws. 



Branchiostegal rays seven. 



Dorsal fins two, separated by a decided interval ; the first behind the vertical 

 of the pectoral fins, pointed in front, triangular, and with nine to fifteen rays ; 

 second divided into two portions by a deep sinus behind its middle, and with 

 its posterior part highest. 



Anal opposite and similar to the second dorsal. 



Caudal fin emarginated, with numerous supplementary rays above and be- 

 low the peduncle. 



Pectoral fins slender, rather long and obliquely rounded behind. 



Ventral fins inferior, little distant (about the width of their bases) and 

 moderately in advance of the pectorals, rather long, and with seven rays, of 

 which the fourth to sixth are longest. 



D. (9) 1015 | 3645. A. 3551. P. 14. V. 7. 



The skull greatly differs from that of Gadus, as is indicated by the frontal 

 depression seen through the skin. The great single frontal bone of the cods 

 is in the Merlucius represented by two ; each is traversed by a crest, which 

 extends towards the front of the orbit, and which is continued from the cor- 

 responding branch of the fork of the supraoccipital crest ; between the fron- 

 tal crests thus placed, there exists a great depression of a triangular form, 

 whose length is nearly twice as great as its anterior width ; the sides of this 

 depression are steep and even scooped out. 



This genus is one of the most trenchant and strongly-marked among fishes, 

 and contains among its representatives some of the most common and widely- 

 distributed species, all the seas of the Northern hemisphere being provided 

 with them. Those species at the same time are themselves objects of con- 

 siderable economical importance, and are also famed for the ravages which 

 they commit on the other inhabitants of the sea. Yet this genus, so cha- 

 racteristic and so peculiar, and concerning which less confusion might be 

 supposed to exist than almost any other, has been singularly misunderstood 

 and received, through the misapprehensions of authors, a number of names 

 which require to be ranked among its synonyms. 



Rafinesque first proposed to take the Linnjean specific name of its type as 

 the generic designation, but soon afterwards, with accustomed fickleness, sub- 

 stituted the name of Onus, and, finally, discovering that such after all was 

 not the true name, corrected it to Merlangus ;* all this was the fruit of the 

 year 1810 ! 



In the " Report, in part, on the Fishes of New York," Dr. Mitchill gave a 

 description of a" hard-featured fish bought in the New York market, November 

 4, 1813," conferring on it the new generic as well as specific name of Stomo- 

 don bilinearis. This is quite a recognizable notice of the common hake of 

 New York and the Eastern coast of the United States ; Mitchill has, however, 

 erroneously assigned only four ventral rays ; he has hazarded no conjectures 

 as to its affinities. In his subsequent memoirs no allusion is made to this 

 name, but the species reappears in the "Memoir on the Fishes of New 

 York," under the name of Gadus merluccius, and again in the " Journal of 

 the Academy of Natural Sciences" as the new species Gadus albidus* 



For some time after, the genus remained in this condition, no one having 

 erred very widely concerning its affinities, and only one author having referred 

 to a new species. Bat in 1855, Dr. Ayres, in California, described a species 

 of that coast as a Merlangus, and Dr. Girard in the East as a supposed 

 new generic type of Trachinoids from the same waters, under the name of 

 Homalopomus Troicbridgii ; the latter gentleman afterwards discovered that 



* " In vece di Onus, ep. 30 [ Onus riali = Gadus mtrluccius, L.l leggete Merlangus." 



1863.] 



