86 ep:port of commissioner of fish and fisheeies. 



couseqnence, acquires an extraordinary thickness, and resembles the giz 

 zard of a fowl ; hence its popular name of "gizzard-fish." The stomach 

 when cleaned and boiled, is a favorite morsel with the Canadian voy- 

 ageurs. 



C—NEW SPECIES OF AEGYROSOMUS AND COEEGONUS. 



By James W. Milker. 



Argyrosomus Agassiz. 



This genus was separated from Coregonus by Professor Agassiz in 

 1850.* The principal character referred to as distinguishing it is that 

 the lower jaw is the longer. The examination of a number of species 

 has discovered, in addition to this character, a constant difference in the 

 form of the supraorbital bone. In Coregonus, it is short and broad, and 

 does not reach the middle of the orbit. In Argyrosomus, it is long and 

 narrow, and extends considerably beyond the middle of the orbit. The 

 premaxillaries in Argyrosomus are much shorter ; and this character 

 and the projection of the lower jaw make the snout more pointed than 

 in the other group. Minute teeth are present upon the premaxillaries 

 and tongue. Professor Agassiz refers to the latter character as if it 

 were peculiar to this genus; but, in the dried heads of Coregonus alhus, 

 (not of Agassiz,) teeth are apparent on the premaxillaries. 



Argyrosomus Hoyi Gill, (MSS.) 



Argyrosomus Eoyi Gill (MSS.); Hoy, Trans. Wise. Acad., vol. 1, p. 100, 1872. 



The Cisco of Lake Michigan,t not to be confounded with the cisco of 

 Lake Ontario, is a fish frequenting the deep waters. It is taken in con- 

 siderable quantities, at depths of from 30 fathoms to 70, and is the prin- 

 cipal food of the salmon or Mackinaw trout. Specimens were sent to 

 the Smithsonian Institution, in 1870, by Dr. P. E. Hoy, of Eacine, Wis., 

 obtained in that vicinity, from which Dr. Gill made diagnostic notes, 

 and adopted the name of Argyrosomus Hoyi. In a list of species of 

 Lake Michigan, published in the Transactions of the Wisconsin Academy 

 of Sciences, Dr. Hoy included Dr. Gill's manuscript name. 



In 1871, while prosecuting work for the United States Commission ot 

 Fisheries, I collected specimens of the species in abundance, all of which 

 were lost in the great fire of Chicago. In 1872, 1 obtained them in Lake 

 Superior, and from one of this collection the following description is 

 made: 



The differences between this species and the common "lake-herring" 

 [A. clu2)ciformis Mitch.) are quite prominent. The orbit in the cisco is very 

 large, encroaching a good deal upon the frontal bones. The froutals are 

 in consequence abruptly diminished in width near the posterior edge of 

 the orbit, and in the superior aspect of the head expose the upper border 

 of the eye. The exposed portion of the shoulder-girdle is of less width ; 



* Lake Superior: its Physical Character, &c., p. 339. 

 tFor account of hahits, see page 35. 



