136 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
highest, others gradually shorter; anal inserted a little anterior to a perpendicular passing half way 
between origins of dorsals; first ray longest, others successively shorter; when the tin is elevated 
its edge is concave; caudal deeply forked, the tips pointed, pectoral notably pointed, extending past 
base of ventral a distance equal to diameter of orbit; ventrals extending to vent. 
Translucent in life. A silvery lateral band 1 scale wide, bright and distinct posteriorly, becom- 
ing indistinct anteriorly; upper edge of lateral band dusky; scales on dorsal part of body edged with 
dark dots; jaws with dark dots; upper part of eye black; the dark, pigmented arachnoid shows 
through the thin skull. 
C. chapalce is closely related to C. grandocule Steindackner. It differs iu having a smaller eye 
and larger scales. The former has 44 to 51 scales in the lateral series and 12 to 14 in a transverse 
series, while C. grandocule has 60 to 62 scales in the lateral series and 15 to 16 in a transverse series. 
Measurements of seven specimens of Chirostoma chapalce. 
Measurements. 
Locality: Laguna de Chapala. 
Length of body in millimeters 
88 
98 
78 
73 
70 
71 
66 
Depth of body expressed in hundredths of length 
19 
18 
18 
18 
19 
19 
18 
Depth of caudal peduncle 
9 
81 
9 
9 
9 
9 
9 
Length of head 
25 
23 
25 
23 
25 
2G 
26 
Distance from snout to occiput 
18 
17 
19 
17 
194 
19 
194 
Tips of lower iaw to occiput 
19 
181 
20 
18 
21 
20 
20 
Width of interorbital space 
6 
6 
0 
6 
64 
64 
64 
Length of snout 
8 
7 
8 
8 
8 
8 
8 
Diameter of orbit 
61 
n 
52 
7 
7 
74 
7 
Distance from snout to spinous dorsal 
54 
52 
51 
53 
50 
52 
Insertion of spinous dorsal to soft dorsai 
14 
13 
14 
13 
14 
15 
14 
Height of longest dorsal spines 
9 
8 
9 
8 
84 
10 
10 
Height of longest dorsal rays ’. 
14& 
141 
15 
14 
16 
16 
16 
Distance from snout to anal tin 
CO 
59 
CO 
57 
57J 
57 
58 
Height of longest anal rays 
10 
14 
16 
16 
17 
18 
18 
Distance from anal to caudal fin 
22 
20 
22 
23 
20 
21 
20 
Length of caudal tin 
23 
21 
24 
24 
23 
25 
25 
Length of pectoral fin 
21 
20 
18 
17 
20 
21 
19 
1 tistance from snout to ventral fin 
43 
41 
43 
30 
41 
41 
42 
Length of ventral fin 
11 
12 
13 
13 
14 
13 
12 
Humber of spines iu lirst. dorsal. . 
4 
5 
5 
4 
4 
5 
4 
Number of rays in second dorsal 
10 
11 
ii 
10 
11 
n 
11 
Number of rays in anal 
20 
20 
21 
18 
20 
21 
19 
Number of rays in pectoral tin 
14 
14 
14 
14 
14 
14 
Number of scales in lateral series 
47 
50 
44 
4(5 
51 
47 
50 
Number of scales in transverse series 
13 
13 
12 
13 
14 
14 
14 
Number of scales between dorsals 
6 
.7 
7 
6 
7 
7 
7 
32 . Chirostoma promelas Jordan & Snyder, new species. 
Type No. 6161, L. S. Jr. Univ. Mus. Collected by J. O. Snyder, in market of Guadalajara, 
Jalisco, Mexico; said to have come from Laguna 
de Chapala, December 23, 1898. 
Head 3.40 in length; depth 4.60; depth of 
caudal peduncle 3.33 in head; eye5.66; snout2.50; 
interorbital space 4.50; height of spinous dorsal, 
3.60; soft dorsal 2.4; anal 2; length of pectoral 
1.60; ventral 2.50; caudal 1.50. D.iv-11. A. 19. 
P. 15. Scales in lateral series 53, 16 in transverse 
series, 9 between dorsals. 
Head slender, triangular; eye smaller, 
nearer to tip of snout than to edge of opercle a 
distance equal to half the diameter of pupil; 
width of preorbital area somewhat greater than 
diameter of pupil; interorbital space slightly con- 
vex; snout pointed; upper jaw projecting a little 
beyond lower ; cleft of mouth aluiost horizontal, 
lips enlarged posteriorly, the lower folding over 
the upper at their junction ; angle of mouth on a 
level with lower part of pupil ; maxillary almost 
vertical in position, its distal end not extending 
backward as far as anterior edge of orbit. Teeth large, curved inward, not arranged in definite 
rows, none on vomer or palatines. Vertebrae 45. A tolerably well-defined lateral line extending 
Fig. 11. — Lateral and dorsal views of head of 
Chirostoma promelas. 
