443 



A. natalis, a species with a broad head and a longer anal fin than the above, 

 (A 24-27). Further information is desirable as to the geographical distribution 

 and any differences of habit of these species. 



The great Catfish of the lakes and larger rivers, (Amiurus nigricans) 

 plate 5, is at once distinguishable by its great size — it may run to a weight of 

 100 lbs. — and its forked tail. The young may be known by the fin-formula 

 (D, I, 5 ; P, I, 9 ; A. 2-5) from the above species. Apart from its only being found 

 in large bodies of water, it appears to share the mode of life of the smaller 

 species, I ut little appears to be known as to the peculiarities, which a species so 

 distinct is sure to possess. 



For completeness sake, reference may be made here to the small Stone-Cats 

 (Noturus) which are inconspicuous on account of their size (4-5 inches), but 

 differ from the Catfish proper in their habits of lurking beneath stones, and in th& 

 length of the adipose fin which is almost continuous with the tail-fin. Two 

 species are reported from the Great Lakes region — N. gyriniis and N. flavus — 

 the latter being characterized by its serrated pectoral spine. 



The Suckers (Catostomid^) are a family of fish which can hardly be said 

 to be of economical importance, for their flesh is coarse, watery and destitute of 

 flavour, but they, like the Minnows, are at least important as furnishing food 

 to the carnivorous fishes. Their great abundance also, especially when they 

 ascend streams in the spring, has caused them to be occasionally used by farmers 

 for fertilizing purposes. 



They differ from the Catfishes in their coat of cycloid scales, the conical 

 head narrowing to the small mouth, which is destitute of the surrounding 

 barbels, but has protractile fleshy lips, and toothless jaws. There are no spines 

 as in the Catfish, the anal fins are always shorter than in that family and 

 there is no adipose tin. The air-bladder is divided into two or three compart- 

 ments, an arrangement which has been supposed to favour sudden changes of 

 the position of the head in swimming, but most probably has some other function^ 



In addition to the genus Catostomus which gives its name to the family, 

 and to which the Common Sucker (C. teres) belongs, four other genera occur in 

 the Lake region, viz.: — Ictiobus, Erimyzon, Minytrema, Moxostoma. 



The first mentioned, including the Buffalo fishes of the Mississippi Valley and 

 one species irom the Great Lakes (/. Thompsoni), is at once distinguished by its 

 long dorsal fin of 27 rays, while the others rarely have half as many ; of these 

 Catostomus, Erimyzon, Minytrema, agree in having the air-bladder divided into 

 two compartments, whereas in Moxostoma it has three. Catostomus embraces 

 comparatively small-scaled forms in which 80-100 scales are found in the course 

 of the lateral line, while Erimyzon, Moxostoma and Minytrema have large scales, 

 from 40 to 50 in the lateral line. 



Of the numerous species of Catostomus, two, G. catostomus, the long-nosed 

 Sucker, and C. teres, the common Sucker, are known to occur in Ontario, the 

 former — the larger of the two — being more abundant northward and westward. 

 It is distinguished by the projecting snout which overhangs the mouth, and by 

 the greater number of scales (95-114) in the course of the lateral line as com- 

 pared with the common species (64-70). Both species indicate their affinity to 

 the next family (Cyprinidce) by the males possessing a special breeding dress 

 in spring, consisting of a rosy lateral band, and numerous excrescences about the 

 head and anal fin. 



