134 
BULLETIN OP THE UNITED STATES FISH COMMISSION. 
Air bladder extending posteriorly to a point a little past insertion of anal. Peritoneum black. 
Vertebras 37. Lateral line represented on the fifth row of scales below the dorsal by a series of partly 
developed pores; scales large, entire, covering head and body except snout, lower jaw, preorbital 
area, and a small space around bases of pectoral fins ; small scales extending for a short distance on 
interradial membranes of caudal. First three dorsal spines of about the same height, the fourth shorter, 
first fully developed dorsal ray longest, the others gradually shorter, edge of fin straight ; anal inserted 
on a perpendicular passing halfway between dorsals, its first fully developed ray longest, edge of fin 
slightly concave; caudal notched; pectorals rounded, extending to bases of ventrals; ventrals falling 
short of reaching vent a distance equal to diameter of orbit. 
Translucent in life, a silvery lateral band with dark upper edge extending from upper part of base 
of pectoral to base of caudal, the band less distinct in region of pectoral fin; scales of back edged 
with fine, dark specks ; snout, lower jaw, top of head, and upper part of eye dusky ; dorsal and caudal 
fins with a little dusky coloring. 
Specimens of E. arge were caught in the same seine-haul with E. jordani. The former differs from 
the latter in having a thicker body, a longer snout, a larger and less oblique mouth, a larger eye, and 
a wider color-band. 
In the drawing accompanying the original description of Eslopsarum jordani the mouth is wrongly 
represented. Of the specimens examined, including some of the types, the mouth is much like that 
of Chirostoma liumboldtianum. The cleft is not straight in outline. The lower lip folds over the upper 
at their union. 
Measurements of ten specimens of Eslopsarum arge. 
Measurements. 
Locality: Rio Verde at Aguas Calientes, Mexico. 
Length of body in millimeters 
56 
63 
58 
53 
54 
53 
53 
51 
51 
52 
Depth of body expressed in lmudredtbs of length 
22 
20 
19 
10 
20 
19 
19 
20 
20 
20 
Depth of caudal peduncle 
9 
8 
8 
9 
9 
9 
8 
9 
9 
84l 
Length of head 
24 
23 
23 
234 
23 
24 
24 
24 
24 
24 
I >istance from snout to occixmt 
184 
174 
17 
18 
18 
17 
18 
184 
18 
18 
Tip of lower jaw to occiput 
20 
184 
18 
19 
19 
18 
19 
194 
19 
19 
Width of interorbital space 
8 
7 
7 
8 
7 
7 
8 
74 
U 
7 
Length of snout 
7 
7 
7 
74 
7 
7 
8 
8 
8 
8 
Diameter of orbit 
6 
6 
6 
6 
64 
6§ 
0 
6£ 
7 
6 
Distance from snout to spinous dorsal - - - . 
52 
52 
52 
50 
53 
52 
53 
54 
52 
52 
Insertion of spinous dorsal to soft dorsal 
15 
14 
134 
13 
13 
14 
14 
13 
15 
14 
6 
9 
8 
7 
7£ 
8 
7 
9h 
8 
Height of longest dorsal rays 
12 
14 
12 
14 
13 
13' 
12 
15 
14“ 
13 
Distance from snout to anal tin 
60 
58 
59 
57 
01 
58 
57 
58 
57 
57 
Heigbtof longest anal rays 
13 
13 
14 
in 
14 
13 
13 
14 
14 
15 
Distance from anal to caudal fin 
23 
23 
23 
24 
25 
23 
24 
23 
23 
24 
Length of caudal fin 
22 
20 
19 
20 
21 
22 
19 
22 
22 
21 
Length of pectoral fin 
15 
154 
15 
15 
15 
16 
16 
16 
15 
16 
Distance from snout to ventral fin 
45 
43 
45 
41 
44 
42 
42 
43 
44 
43 
Length of ventral tin 
10 
10 
9 
10 
10 
10 
10 
11 
10 
10 
Number of spines in first dorsal 
4 
3 
4 
4 
3 
4 
3 
4 
4 
4 
Number of rays in second dorsal 
8 
8 
8 
9 
9 
8 
8 
8 
9 
9 
Number of rays in anal 
15 
17 
16 
16 
14 
14 
14 
14 
15 
14 
Number of rays in pectoral 
13 
14 
13 
14 
13 
13 
12 
13 
13 
13 
Number of scales in lateral series 
40 
38 
40 
39 
40 
38 
38 
38 
36 
39 
Number of scales in transverse series 
11 
12 
11 
11 
10 
10 
10 
11 
JO 
10 
Number of scales between dorsals 
5 
5 
4 
5 
5 
5 
4 
4 
5 
5 
30. Chirostoma humboldtianum (Cuvier & Valenciennes). Pcscado Blanco de Chaleo. 
Specimens of Chirostoma humboldtianum were very plentiful in the markets of the City of Mexico. 
They were said to come from the Lago de Chaleo. This species is darker in color and much less 
translucent than any other Chirostoma collected by us The number of vertebrae is 44. It is the only 
species yet known referable to the typical subgenus Chirostoma. 
