130 BULLETIN OF THE BUREAU OF FISHERIES. 
10. Pogonichthys macrolepidotus Ayres. Split-tail. 
Leuciscus macrolepidotus, Ayers, Daily Placer Times and Transcript, 1854, May 30, San Francisco. 
Pogonichthys inexquilobus, Baird & Girard, Proc. Ac. Nat. Sci. Phila. 1854, p. 136, San Joaquin River. 
Pogonichthys macrolepidotus, Jordan & Evermann, Fishes North & Mid. Amer., pt. 1, p. 223, 1896. 
Head 4 in body; depth 4.2; eye 4 in head; interorbital 3; snout 3.2; dorsal 10, anal 9, pectoral 15, 
ventral 10; scales 11-59-6; teeth 2, 5-5, 2; upper lobe of caudal 2.4 in body. (Measurements based on 
a specimen 140 mm. long, from Pollasky.) 
In general the head is somewhat conical, the eye is rather large and placed anteriorly; the mouth 
is nearly horizontal, the lower jaw included, the maxillary reaching a vertical between nostril and eye, 
a small barbel at its tip. The gillrakers are somewhat longer than in other western minnows. Body 
long, scarcely compressed, but little arched; caudal peduncle deep, half as deep as body; lateral line 
slightly decurved. Dorsal inserted in middle of body, its anterior rays equal to head and twice as long 
as posterior rays; anal similar to dorsal, but smaller; ventrals inserted under third ray of dorsal; caudal 
very large, deeply forked, the upper lobe much longer than the lower and nearly twice as long as the 
head. Length 12 inches. Readily distinguished by the long upper lobe of caudal fin. 
The extremes of measurements are: 
0.24— 0.27 | Depth of caudal peduncle...-...-.-..-..---22---.- 0.11-0. 12 
0.22- 0.25 | Length of caudal peduncle.............-.--..-:..- 0.15-0.18 
0.06-- 0.075 | Upper lobe of caudal fin... . 0. 42-0. 45 
0.075-0.08 | Lower lobe of caudal fin ./..............-----.-..- 0.33-0.36 
0.07— 0.08 | 
The following summary of head measurements shows the relations between the size of the head and 
the length of the fish: 
Number of specimens having head— 
Length of fish. —— 
0.24. | 0.245. | 0.25. | 0.255. | 0.26. | 0. 265. 0. 27. 
Millimeters. 
70-79 he ee eee 
le | 
The variation in the size of the eye with reference to the size of the fish is shown in the following: 
Number of specimens having 
Length of fish. Sim 
0.06. | 0.065. 9. 07. 0. 075. 
Millimeters. 
110-119. 
| 120-129... 
130-142 
The difference between the lengths of the caudal lobes varies with the size of the fish, being greater 
in larger specimens, as shown in the following table: 
Number of specimens having 
difference between lobes of 
Length of fish. caudal fin amounting to— 
0.07. | 0.08. | 0.09. 0. 10. 
Millimeters. 
70-79... sialeie ere wits Sse coe eee ees ance ater 
80-89......- 
110-119. .... 
120-129. a 
NB OM 142 Soc ins «Soe eee cee ee eee eae 
