FISHES FROM THE RIVERS OF MEXICO. 
123 
Notropis calientis are with Notropis cayuga, N. jordani, and others of the subgenus Chriope. The species 
may he distinguished by its small eye, the short, rounded snout, deep body, short lateral line, and 
rounded fins. 
Measurements of ten specimens of Notropis calientis. 
Measurements. 
Locality: Rio Verde, Aguas Calientes, 
Mexico. 
Length of body in millimeters 
42 
44 
42 
41 
40 
38 
36 
36 
34 
32 
Depth of body expressed in hundredths of length. 
28 
29 
29 
28 
30 
29 
30 
26 
26 
26 
Depth of caudal peduncle 
10 
10 
10 
11 
12 
10 
10 
12 
10 
10 
Length of head 
26 
25 
26 
27 
27 
25 
25 
26 
26 
27 
Distance from snout to occiput 
20 
21 
19 
21 
20 
20 
20 
20 
21 
20 
Width of interorbital space 
10 
8 
10 
10 
10 
9 
10 
10 
9 
10 
Length of snout 
7 
7 
74 
7 
7 
74 
7 
7 
8 
7 
Diameter of orbit 
7 
7 
7 
7 
7 
6.1 
61 
6 
7 
7 
Distance from snout to dorsal fin 
63 
53 
52 
54 
53 
52 
52 
51 
55 
52 
Height of longest dorsal rays 
20 
22 
20 
22 
22 
22 
21 
23 
21 
23 
Distance from snout to anal tin 
67 
70 
69 
69 
70 
70 
70 
68 
68 
08 
Height ot longest, anal ravs 
18 
16 
17 
18 
17 
17 
17 
19 
19 
18 
Distance from anal to caudal fin 
24 
24 
24 
24 
23 
23 
25 
25 
23 
26 
Length of caudal fin 
24 
22 
25 
26 
26 
20 
25 
24 
25 
23 
Length of pectoral fin 
18 
16 
16 
17 
18 
18 
17 
20 
17 
17 
Distance from snout to ventral fin 
52 
52 
53 
53 
56 
53 
51 
53 
50 
52 
Length of ventral fin 
18 
16 
15 
17 
16 
17 
17 
16 
15 
16 
Number of rays in dorsal fin 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
Number of rays in anal fin 
7 
8 
7 
7 
7 
7 
7 
7 
7 
7 
Number of scales before insertion of dorsal 
14 
16 
15 
14 
15 
17 
16 
17 
17 
16 
Number of scales in lateral line 
33 
34 
32 
35 
35 
36 
35 
34 
36 
34 
XYSTROSUS Jordan & Snyder, new genus. 
Type, Xyslrosus popoclie, new species. Body long, compressed; interorbital space low and flat; 
mouth terminal, oblique; jaws subequal; premaxillary protractile. No barbel. No pseudobranchiae. 
Gillrakers 66, long, slender, crowded on arch. Teeth 4-4, hooked, grinding surface oblique, grooved. 
Alimentary canal about twice as long as body. Peritoneum dusky. Lateral line complete, decurved 
above pectorals. Scales 61, evenly distributed over body. Fins falcate; dorsal inserted directly above 
insertion of ventral; caudal deeply forked; anal basis short. 
The genus Xyslrosus is allied to Notropis, differing in the long gillrakers, the small scales, and 
the absence of pseudobranchise. 
12. Xystrosus popoche Jordan & Snyder, new species. Popoclie. Fig. 5. 
Type No. 6151, L. S. Jr. Univ. Mus. Locality, Laguna cle Chapala, near Ocotlan, Jalisco, Mexico. 
Collected by J. O. Snyder, December 26, 1898. 
Head 3.5 m length; depth 4.5; eye 4.66 in head; snout 3.60; interorbital space 2.60; depth of 
caudal peduncle 2.5; height of dorsal 5 in length; anal 6; length of pectoral 6; ventral 6.25; caudal 4. 
D. 8. A. 7. Number of scales in lateral line 61; between dorsal and occiput 24; between dorsal and 
lateral line 16; number of dorsal rays 8; anal 7 ; pectoral 16. 
Body long and slender; caudal peduncle deep, compressed; head long, its upper contour slightly 
concave; interorbital space broad and flat; eye large, its longitudinal diameter contained 2 times 
in interorbital space; snout sharp, slightly turned up at end; mouth large, oblique; lips thin, 
