Jordan and Evermann. — Fishes of JSTorth America. 467 



232. ARGYROSOMUS, Agassiz. 



(CiSCOES.) 



Argijroiomns, Agassiz, Lake Superior, 339, 1850, (Wiipei/Virmis = arledi). 

 AUosomus, Jordan, Manual Vertebrates, Ed. 2, 3G1, 1878, {tnVibfe). 



This genus is very close to Coregonus, from whicli it differs in the 

 larger mouth and more produced jaws, the premaxillaries being placed 

 nearly horizontally, and the lower jaw decidedly projecting beyond them. 

 Gill rakers very long and slender, about 30 on lower limb. Vertebne 55. 

 These characters are associated witli the greater voracity and, in general, 

 greater activity of the species of Anjyrosomus. The species are numerous 

 in the northern parts of Europe, Asia, and North America, and all are 

 valued as food, (apyvpoc, silver; awfia, body.) 



Arotrosomvs: 

 a. Body elongate, herring-shaped; scales small, uniform, the free edges convex. 



b. Lower fins pale or merely tipped with dusky ; scales punctate with dark points. 



c. Eye large, not much, if any, shorter than snout in adult, its length 3}-^ to 4J/2 in 

 head. 

 d. Head long, 4 in body; body slender, its depth 5 to 6 in length; distance from 

 occiput to snout 2J^ in distance from occiput to dorsal; teeth on tongue; 

 maxillary 3 in head. osmeriformis, 763. 



dd. Head long, 4'.j in length; distance from occiput to tip of snout nearly half its 

 distance to front of dorsal fin; pectorals short, reaching about half way 

 to Tentrals. 

 e. Maxillary 3^/^ to SJ^ in head; lower jaw projecting; gill rakers long and 

 numerous, about 16 + 30. artedi, 764. 



ee. Maxillary longer, 23 to 3 in head; gill rakers fewer, about 14 -^ 25. 



HOYi, 765. 



ddd. Head shorter, about 5 in length; distance from occiput to tip of snout about 



I distance to front of dorsal fin; pectorals long, reaching more than 



half way to ventrals; maxillary Z)/^ in head. pusillus, 766. 



cc. Eye small, shorter than snout, about 5 times in length of head. 



/. Head short, about 5 in length. 



g. Body rather slender, the depth equal to length of head; distance from occi- 

 put to snout 2)2 to 2" 3 in its distance from dorsal; base of dorsal short. 



LUCIDUS, 767. 



gg. Body deeji, the depth in adult greater than length of head; distance from 



occiput to snout 2J3 to 2J^4 in distance from occiput to dorsal; base of 



dorsal longer. laueett.e, 768. 



ff. Head long, 4 to 4}-^ in length; lower jaw strong. 



h. Maxillary very long, 2V^ in head; lower jaw much projecting; gill rakers 

 about 15 + 28; distance from snout to occiput 2i in distance from 

 occiput to dorsal; mouth larger than in A. artedi or in related species. 



PHOCNATHl'S, 769. 



fcfc. Lower fins all blue-black; body robust; mouth large; gill rakers numerous, 18 +30; 



eye large, 4J in he.ad. nigripixnis, 770. 



Allosomi'S (aAAos, different; crcifia, body): 



aa. Body short, deep, compressed, the curve of back similar to that of the belly; scales large, 



larger forward and closely imbricated, the free margin little convex. 



t. Jaws equal when closed or lower slightly projecting; deptli 3 in length; mouth rather 



small; maxillary 3}-^ in head; eye 4J.2 in head; gill rakers about 16 •• 31, long and 



elender, about equal to eye. tullibee, 771. 



