FISHES FROM THE RIVERS OF MEXICO. 
135 
Measurements of ten specimens of Chirostoma humboldtianum. 
Measurements. Collected in markets of City of Mexico. 
Length of hody in millimeters 
Depth of body expressed in hundredths of length 
Depth of caudal peduncle 
Length of head 
Distance from snout to occiput 
Tips of lower jaw to occiput 
Width of interorbital space 
Length of snout 
Diameter of orbit. 
Distance from snout to spinous dorsal 
Insertion of spinous dorsal to soft dorsal 
Height of longest dorsal spines 
Height of longest dorsal rays 
Distance from snout to anal fin 
Height of longest anal rays 
Distance from anal to caudal tin 
Length of caudal tin 
Length of pectoral fin 
Distance from snout to ventral fin 
Length of ventral fin 
Number of spines in first dorsal 
Number of rays in second dorsal 
Number of rays in anal 
Number of rays in pectoral 
Number of scales in lateral line 
Number of scales in transverse series 
Number of scales between dorsals 
18G 
172 
182 
187 
170 
162 
160 
151 
154 
148 
22 
224 
204 
24 
20 
21 
19 
22 
20 
21 
9 
9 
9 
8 
8i 
9 
8 
9 
9 
9 
27 
29 
274 
264 
28 
21b 
27 
264 
264 
27 
21 
21 
21 
214 
204 
21 
204 
20 
20 
21 
22 
22 
22 
23 
214 
22 
22 
21 
21 
22 
7A 
8 
8 
7 
7 
7£ 
74 
7 
7 
7 
104 
lOo 
10 
9 
9 
9 
9 
9 
9 
9 
5| 
6 
54 
54 
6 
54 
54 
6 
6 
6 
524 
56 
54 
54 
55 
54 
53 
52 
53 
52 
124 
14 
134 
12 
13£ 
12 
114 
13 
12 
124 
•1 
64 
74 
6 
04 
n 
8 
7 
8 
8 
14 
114 
14 
12 
12 
13 
14 
13 
13 
134 
63 
64 
63 
62 
604 
60 
62 
60 
61 
59 
14 
124 
14 
124 
13 
13 
13 
13 
14 
14 
22 
21 
21 
22r 
20 
23 
23 
22 
22 
23 
20 
19 
19 
20 
Pi 
194 
20 
19 
19 
20 
20 
17 
18 
18 
17 
19 
19 
18 
18 
20 
47 
48 
47 
47 
46 
45 
45 
45 
45 
40 
12 
11 
11 
11 
10 
12 
12 
11 
11 
124 
6 
4 
5 
5 
4 
5 
4 
5 
5 
4 
11 
12 
11 
11 
10 
10 
11 
11 
10 
12 
19 
18 
18 
18 
19 
18 
18 
19 
19 
18 
15 
14 
15 
14 
14 
15 
14 
15 
14 
14 
54 
50 
52 
52 
50 
54 
54 
55 
55 
54 
15 
15 
15 
14 
14 
14 
15 
14 
14 
15 
7 
6 
7 
6 
7 
8 
7 
8 
7 
8 
Fig. 13 . — Chirostoma cliapalce Jordan & Snyder, new species. Type. 
Subgenus LETHOSTOLE Jordan & Evermann. 
31. Chirostoma chapalae Jordan & Snyder, new species. Pescado Blanco de Chapala. Fig. 13. 
Type No. 6155, L. S. Jr. Univ. Mus. Locality, Laguna de Chapala near Ocotlan, .Jalisco, Mexico. 
Collected by J. O. Snyder, January 2, 1899. 
Head 4 in length ; depth 5.5 ; depth of caudal peduncle 3 in head ; eye 3.66 ; snout 3.2 ; interorbital 
space!; height of spinous dorsal 2.66; soft dorsal 1.75; anal 1.60; length of pectorals 1.25; ventrals 
2.20; caudal 0.9. D. m-10. A. 21. P.14. Scales in lateral series 49; transverse series 13; between 
dorsals 6. 
Body slender, compressed, its deepest part below first dorsal. Eye large, nearer to tip of snout 
than to posterior edge of opercle, a distance equal to 1.5 times the diameter of pupil. Interorbital space 
convex, its width pbout equal to diameter of pupil or to preorbital area. Lower jaw projecting a 
little beyond tip of upper. Mouth oblique; lips thickened posteriorly, lower folding over upper at 
their union; premaxillaries anteriorly on a level with center of pupil ; maxillary nearly vertical, its 
distal end in advance of a vertical from anterior edge of orbit a distance equal to two-thirds diameter 
of pupil. Teeth minute, in bands, not arranged in definite rows; no teeth on vomer or palatines. 
Gillrakers on first arch 30, very slender, the length of longest equal to diameter of orbit. 
Peritoneum black. Air bladder very large, extending posteriorly to a point above middle of 
anal fin. Vertebrte 45. A well-defined lateral line extending along body on eighth row of scales below 
first dorsal. Scales large, cremate, not notably reduced in size nor closely crowded together on any 
part of body, except a small postoccipital patch ; those anterior to pectorals small; scales extending 
on basal two-thirds of interradial membranes of caudal; lower jaw, snout, and preorbital space 
naked. First 2 spines of dorsal highest, the following 2 a little shorter ; first ray of second dorsal 
