FISHES OF THE KLAMATH BASIN. 
9 
before dorsal obliquely downward and backward to lateral line, and 5 or 6 between base of ventrals 
and lateral line. One specimen bas the formula 12-56-7, but is entirely exceptional. Ten specimens 
examined have 20 to 23 oblique series crossing median line in front of dorsal fin. The front of dorsal 
is slightly behind insertion of ventrals in adults, hardly noticeably so in young, always nearer base 
of caudal than tip of snout. Both dorsal and anal have straight margins when the fins are spread. 
The following table records the fin rays in 25 specimens. The single specimen noted with 10 
ventral rays had 9 rays in the ventral of the other side. 
Pins. 
No. of 1 
specimens. 
No. of 
rays. 
Dorsal 
4 
8 
19 
9 
2 
10 
| Anal 
1 
7 1 
24 
Ventral 
2 
8 
22 
9' 
1 
10 
The pectorals fall far short of the ventrals, and the ventrals reach to or nearly to the vent. 
As in other related species, the color is dark steel-gray above with greenish luster, growing 
lighter on lower half of sides. Belly white. Lower half of sides coarsely specked with black. Fins 
all dusky. No dark stripe along sides of head or body, and no orange on head or in axil of fins. 
The following table gives proportionate measurements of parts in four specimens from Upper 
Klamath Lake, the unit of measurement being hundredths of the standard length from tip of snout 
to base of caudal : 
Measurements. 
No. 1. 
No. 2. 
No. 3. 
I No. 4. | 
Total length in millimeters 
206 
155 
130 
100 
Length of head 
30 
27 
274 
26 
Length of snout 
84 
8 
74 
64 
Diameter of eye 
51 
54 
6 
7 
InterorLdtal width 
10 
94 
94 
Length of maxillary 
84 
74 
74 
74 
Depth of body 
261 
29 
274 
25 
Depth of caudal peduncle 
12 
12 
114 
114 
Length of caudal peduncle 
20 
21 
21 
21 
Distance, snout to front of dorsal ... 
554 
53J 
53 
521 
Distance, snout to front of ventrals. 
53 
52 
52 
52 
Length of base of dorsal 
13J 
134 
131 
13§ 
Length of base of anal 
9 
91 
9| 
9 
Height of dorsal 
19 
17 
194 
194 
Height of anal 
151 
13 
16" 
14 
Length of pectorals 
18 
17 
174 
18 
Length of ventrals 
17 
16 
154 
16 
Numerous specimens were collected in Upper Klamath Lake and in Lost River, where it is the 
most abundant species. Others have been examined from Scott River, Siskiyou County, California 
(tributary to the Klamath River), collected by Mr. R. C. McGregor. It seems very improbable that 
this species should be identical with R. parovanus Cope, from the Utah Basin, a species which has not 
appeared in any recent collection. The representatives of this Great Basin type of Rutilus are so very 
similar that the status of B. parovanus can not be determined from current descriptions. Material 
from the other lakes in southern Oregon must also be carefully compared with the Klamath form. 
B. thalassinus from Goose Lake seems to agree in all the details assigned, but other specimens from 
Silver, Chewaucan, and Warner lakes, identified by Cope with Rutilus formosus (Girard), have smaller 
scales below the lateral line than we have found in any specimen of B. bicolor. 
10. Agosia klamathensis Evermann & Meek. 
Agosia klamathensis Evermann & Meek, Bull. U. S. Fish Comm. 1897. Pelican Bay, Upper 
Klamath Lake. ’ 
The Agosia of the Klamath Basin has its closest allies in A. yarrowi and A couesii of the Upper 
Colorado River. These seem to have the fins strongly falcate, at least in adults, while the Klamath 
form has the outlines of dorsal, anal, and caudal lobes broadly rounded, even in adult breeding males. 
The dorsal also averages farther forward in the Klamath species, being usually .located midway 
between base of median caudal rays and middle of snout. 
