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. 
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, 1, 5; P,1,9; A. 25) 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, l-ut little appears to be known as to the peculiarities, which a species so 
_ distinct is sure to possess. : | 
4 The great Catfish of the lakes and larger rivers, (Amiwrus nigricans) 
¥ 
For completeness sake, reference may be made here to the small Stone-Cats 
_ (Notwrus) 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 the 
length of the adipose fin which is almost continuous with the tail-fin. Two 
species are reported from the Great Lakes region—WV. gyrinus 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 fin. 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, Krvumyzon, Minytrema, Moxostoma. 
; The first mentioned, including the Buffalo fishes of the Mississippi Valley and 
one species from the Great Lakes (J. Thompson1), is at once distinguished by its 
long dorsal fin of 27 rays, while the others rarely have half as many; of these 
Catostomus, Hrimyzon, 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 seales 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, C. 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 (Cyprinide) 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. : 
