1904.] FOWLER— DESCRIPTION OF COREGONUS XELSOXII. 451 



DESCRIPTION AND FIGURE OF COREGONUS NELSONII 



BEAN. 



(Plates VIII and IX.) 

 BY HENRY W. FOWLER. 



{Read December 16, 1904.) 



Through the courtesy of Drs. Horace Jayne and M. J. Greenman 

 I have recently had the opportunity of examining several large 

 examples of the above White Fish received at the Wistar Institute 

 of Anatomy in Philadelphia. As this species is only known from 

 Dr. Bean's description and several references, it is of value to have, 

 more detailed information for the comparison of the species. 



CoREGONUS NELSONII Bean. 



Froc. U. S. Nat. Miis., VII, 1884 (1885), p. 48. Nulato, Alaska. 

 (E. W. Nelson.) 



Heads; depth 4; D. in, 11; A. iii, 9; P. 11, 16; V. I, 10; 

 scales 81 in lateral line to base of caudal ; 11 scales between origin 

 of dorsal and lateral line, and 9 between latter and origin of ven- 

 tral ; about 33 scales before dorsal ; width of head i| in its length ; 

 depth of head li; snout 4; eye yl-; maxillary 4^; interorbital 

 space 3^^; mandible 3 j ; second dorsal ray i^; first anal ray 

 if; length of pectoral i|-; ventral i^^; least depth of caudal 

 peduncle 2^. 



Body elongate, oblong, robust, compressed, sides flattened, back 

 hardly elevated, and profiles similar though upper is a little more con- 

 vex or gibbous anteriorly than lower. Greatest depth about origin 

 of ventral. Caudal peduncle stout, compressed, and its least depth 

 about equal to its length. 



Head small, compressed, sides flattened, and upper profile a 

 little concave. Snout convex, a little produced and broad. Eye 

 small, circular, and placed near first third in length of head. 

 Mouth inferior, small, gape a little curved in profile, and its width 

 much greater than gape. Lips rather thick or fleshy. No teeth 

 either in jaws, on roof of mouth or on tongue. Tongue not free. 

 Nostrils adjoining, a little nearer front of eye than tip of snout, and 

 anterior with a fleshy or cutaneous rim, posterior margin enlarged a 

 little and more or less conceals posterior nostril. Interorbital space 

 convex, elevated more medianly. Opercles with striae. Opercular 

 flaps rather broad. 



