GREAT LAKES COREGONIDS 



377 



weather at this time of the year the fish are not followed after they move out of 

 the bay. 



These are the only known spawning grounds of the species, though others are 

 certainly in existence in Lake Huron and possibly in Georgian Bay. The location 

 of the spawning grounds in Colpoys Bay and Owen Sound and along the shore south 

 of Cape Rich opens the way for further investigation of the life history of the long- 

 jaw. It should be practicable to secure eggs for artificial propagation, should such 

 a step be desirable. Something could be learned about the conditions necessary 

 for the development of the egg, also, and for the maintenance of the fry. 



FOOD 



Thirty stomachs were examined by Doctor Hubbs from specimens taken off 

 Alpena, Mich., in September, 1917, in 60 fathoms and deeper. Mysis constituted the 

 only food found in most of these stomachs. About one-third of the fish had eaten 

 a little sand and plant remains of one kind and another. Pisidium, clay, fish scales, 

 and cased invertebrate eggs of some kind were found in an occasional stomach. One 

 specimen taken off Bay City, Mich., on October 29, 1921, had eaten larvae of the 

 May fly (Hexagenia) and some cased invertebrate eggs. 



LEUCICHTHYS ZENITHICUS Jordan and Evermann 



The Short-jawed Chub (Fig. 16) 



Argyrosomus zenithicus Jordan and Evermann, 1909, pp. 169-171, Lake Superior, off Isle Royale. 

 Leucichthys zenithicus Jordan and Evermann, 1911, pp. 29-30, Lake Superior; Dymond, 1926, 



p. 65, PI. VI, Lake Nipigon. 

 Argyrosomus hoyi Milner, 1874a, pp. 86-87, in part, Lake Superior; Evermann and Smith, 1896, 



pp. 310-312, pi. 22, in part, Lake Michigan. 

 Leucichthys hoyi Jordan and Evermann, 1911, pp. 28-29, fig. 14 and PI. Ill (not V), Lake Michigan. 



Leucichthys zenithicus has been described from Lake Superior and occurs also 

 in Lakes Michigan, Huron, and Nipigon. In all four bodies of water it is represented 

 by elongate, subterete fishes of relatively moderate size, with short, usually included 

 mandible, relatively long snout and maxillary, shallow head, and a moderate number 

 of gill rakers and lateral-line scales. These forms inhabit moderate depths and 

 spawn in the fall. The Michigan and Huron races differ from the typical race in 

 having a shorter head and pectoral fins and reduced pigmentation, especially on 

 the maxillary. The Huron race also has somewhat fewer gill rakers. The Nipigon 

 race has fewer gill rakers, fewer scales in the lateral line and scale rows, a relatively 

 larger head, eye, and snout, and a slightly deeper body than the typical race. It is 

 also paler in color and less pigmented. The Huron race spawns in September and 

 October; the rest in October and November. 



Type 



The type is a male specimen (catalogue No. 62517, U. S. National Museum) 

 278 millimeters in length, taken "in September, 1908, in deep water off Isle Royale." 

 Counts of certain multiple parts and proportional lengths for this specimen are 

 shown in Table 25. 



