NATURAL SCIENCES OF PHILADELPHIA. 233 



scription), while with Bonaparte the genus Pollachius has been accepted for M. 

 carbonar iu's. I shall not attempt any justification of this error, as it un- 

 doubtedly is, for I myself entertain no doubt that all of the preceding names 

 are referrible to one and the same species. Evidently the M. leptocephalus 

 has no affinity to the true Merlangi. 



In a moderately large specimen, the height is contained about 5 times in the 

 extreme length, and 4| times to the point of the caudal peduncle ; the head 

 4 times in the former, and 4 times in the latter. The first dorsal is about as 

 high or higher than long and about two-thirds shorter than the second. The 

 rays are indicated in the following formula : 



D. (12) 13 | 1821 | 1921. A. (21) 2427 1 18-20. 



Genus BOREOGADTJS GKinther. 



BOREOGADUS POLARIS Gill. 



Gadus ffiglifinus Fab., Fauna Groenl., p. 142. 



Merlangus polaris Sabine, App. Parry's Voyages, p. ccxi. 1824. 



Gadus Fabricii Rich., F. B. A., p. 245 ; Gthr., iv. p. 336. 



Gadus polaris Rich., F. B. A., p. 247. 



Gadus agilis Reinh., Vid. Selks. Afh., vii. g. 126. 



Pollachius polaris Gill, Cat., p. 48. 



Hab. Greenland and Polar seas. 



Dr. Giinther has placed this species in a section of his genus Gadus named 

 Boreogadus, and characterized by having the lower jaw longest ; teeth in the 

 outer series of the upper jaw stronger than the others. To it were referred 

 the Gadus fabricii of Richardson (B. polaris), G. Esmarkii Nilsson, the Mer- 

 langus productus of Ayres, which belongs to the subfamily of Merluciinse, and 

 has not the characters of the section ; and, lastly, the Gadus poutassou of Risso 

 which is the type of the genus Brachymesistius. The Merlangus polaris, how- 

 ever, is the type of a genus distinct from Pollachius and departs from that 

 genus in its larger mouth, enlarged teeth of the outer row in the upper jaw, 

 the extension forwards of the branchial aperture above, obsolescence of 

 the lateral line behind and form of the pectoral fins. The single spe- 

 cimen which I have seen has also the caudal fin unequally lobed, the 

 upper lobe narrowed and rounded behind, the lower triangular and angu- 

 lar ; it is possible, however, that the peculiarity may not be normal, as no 

 mention has been made of it by others. 



Genus GADUS (Artedi) Bon. 

 Morrhua Cuv. 



This genus, as now restricted, excludes the common Haddock and the 

 Gadus minutus of Linnaeus, the former of which is taken as the type of the 

 genus Melanogrammus and the latter as that of the genus Brachygadus. The 

 American species of Gadus have been involved in considerable confusion. 

 There are two very distinct species found along the Eastern coast northwards to 

 Hudson's Bay. One of these is at least nearly allied to the common cod of 

 Europe, and has been known among modern American naturalists under the 

 name of Morrhua americana ; the second is the "torn cod " or " frost fish " of 

 the people, and is quite distinct from any European species. 



In addition to these, two other species have been attributed to America, 

 both being inhabitants of the Greenland seas ; one has been identified with 

 the European cod, and the other has been named Gadus ojac and ovak by 

 Richardson and Reinhardt, while by Giinther it has been considered as a 

 variety of the common cod. 



Finally, Giinther, on the authority of Mitchill, identifying the Gadus mor- 

 rhua of that author with its Linnaean homonym, while referring the same 

 author's G. callarias to the synonymy of G. tomcodus, has stated the true 

 G. morrhua to be found southwards to New York. 



1863.] 17 



