128 BULLETIN OF THE BUREAU OF FISHERIES. 
The teeth are usually 5-5, but sometimes 4-5 in specimens from Kings River at Centerville. 
The horny sheath of the lower jaw is developed in a few of the specimens from almost every locality. 
Its presence is a remarkable feature and one that is ordinarily considered of generic value. It is, how- 
ever, indifferently present or absent in this species and in Rutilus symmetricus. 
Loca DistRIBuTioNn. 
Locality. Stream. Jeasin division. Collector. Name as reported. Authority. 
Sacramento River...) Sacramento ..| Heermann..._........ Lavinia exilicauda) Girard, 1854 and 
1858. 
eee (soe oes Ayres................| L. compressa.....| Ayres, 1854a. 
San Joaquin River .. Sdone -| Newberry . .-| L. exilicauda Girard, 1857. 
San Franciso market.|......-.-......----- -do.. Lockingtor padOesees -| Lockington. 
| Clear Lake. . = SOrdan= sas ene ae Bt eam .| Jordan & Gilbert. 
United States hatch-| Battle Creek. - =e = E ao | Oe ed Oba eo ee aeee . 
ery- 
Red Bluth sesse = ...| Sacramento River - 
Chico Bridge .--....--|-..-- dot se- 5-2-3: 
Jacinto. --=--_- Bese! oar Ss ses 
Wilsons Farm. ..-.-..|...-- GOseaeaen eee 
20 miles below Grimes |. --- - dozna So eS 
Mouth of Feather }....-. GAS me soot eee 
River. 
Marysville. .-..-..... Feather River....... 
Oroville} 22 see Osborn ac J liesaa Gotsee snes 
Grass Valley-.- -| Antelope Creek -..-- a5 -| Rutter & Atkinson ... 
Sacramento. --- -| Sacramento River . . Se -| Rutter & Scofield .... 
Folsom... -..--- American River- ..-- = -| Rutter & Chamberlain’ 
Rio Vista....-- Sacramento River... ..... = aliewad d 
Collinsville_.-----~-:-|---.- (GES See Roane od Becme Me sencead HaoSe 
Black Diamond.-.....! Suisun Bay...-.-.--...-.- 
Antioch... --.-- - San Joaquin River -. Rutter & Chamberlain 
Parrot Ferry Stanislaus Rutter & Atkinson ... 
Livingstone. - Merced River--- d 
Raymond. . Fresno River... 
Pollasky- ---- . San Joaquin. 
Centerville China Slough 
D Kings River. - 
Kaweah River. - 
Rice. souleustsdoc-s-eiee te ee Ee ome i -....-.---.-| Leueosomus occi- | Girard, 1854, 1858, 
| dentalis. and 1859. 
Tule Rivery:.--.5-54 eee Rutter & Atkinson ..- Devine exilicau- 
| a. 
| Pose: Creeks coos so soefe= ce Heermann...........- Leucosomus occi- |Girard, 1854, 1858, 
dentalis. and 1859. 
9. Mylopharodon conocephalus (Baird & Girard). Bluefish; Hardhead. 
Gila conocephala Baird & Girard, Proc. Ac. Nat. Sci. Phila. 1854, p. 135, San Joaquin River. 
Mylopharodon robustus, Ayres, Proc. Cal. Ac. Nat. Sci. 1855, p. 38, San Francisco. 
Mylopharodon conocephalus, Jordan & Evermann, Fishes of North & Mid. Amer., pt. 1, p. 219, 1896. 
Head 4 in body; depth 4.6; eye 4.5 in head, interorbital 3, snout 3; depth of caudal peduncle 2.8 in 
head, its length 1.2; dorsal 9; anal 9; pectoral 15; ventral 9; scales 18—74-8; teeth 2, 54, 2, the last two of 
of the first row molar, the others hooked. (Measurements based on a specimen 163 mm. long, from Merced 
River at Benton Mill.) 
The body is heavy, slightly compressed, regularly tapering to the short conical head and the slender 
caudal peduncle, mouth slightly oblique, terminal, the premaxillary not protractile, the lower jaw 
slightly shorter than the upper, the maxillary extending almost to vertical through anterior margin of eye; 
the lateral line slightly decurved; origin of dorsal about in middle of body, high anteriorly, its longest ray 
1.4 in head; ventrals inserted slightly in advance of dorsal, their tips reaching anal; caudal broad, deeply 
forked, the middle rays nearly 2 in longest, the lobes equal. 
A large minnow resembling Ptychocheilus but readily distinguished by the ridge of skin connecting 
the premaxillary with the top of the head. The head isalso much shorter. This is the most abundant 
fish in the upper Pitt River and in some of the localities in the foothills. 
