FISHES-CYPRINIDAE-MYLOPHARODON. 
215 
3. MYLOCHEILUS FRATERCULUS, Grd. 
Plate XLY, Figs. 1 —4. 
Spec. Char. —Head entering five times and a half in the total length. Snout sub-conical. Posterior extremity of maxillary 
reaching a vertical line intersecting the nostrils. Diameter of the eye contained five times in the length of the side of the head. 
Anterior margin of dorsal fin nearer the insertion of the caudal than the extremity of the snout. Base of anal fin contained 
twelve times in the total length. 
Syn. —Mylocheilus fraterculus, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 169. 
This species is closely allied to the preceding one by the shape of its pharyngeal hones, differ¬ 
ing from it by a more slender body, mucb smaller head, and a larger eye. The dorsal and 
pectoral fins are likewise smaller, but there is no appreciable differences in the number of the 
rays. 
D 1, 8 + 1 ; A 2, 9 ; C 7, 1, 9, 8, 1, 7 ; Y 1, 10 ; P 19. 
The scales are also irregular in their outline, and proportionally deeper. They appear to be 
a good deal smaller on the abdominal region than on the dorsal region. 
lieferences to the figures .—Plate XLY, fig. 1, represents Mylocheilus fraterculus , size of life. 
Fig. 2, a scale from the dorsal region. Fig. 3, a scale from the lateral line. Fig. 4, a scale 
from the abdominal region. 
List of specimens. 
Catal. 
No. 
Correspond’g 
No. of teeth. 
No. of 
spec. 
Age. 
Locality. 
When 
collected. 
Whence obtained. 
Nature of 
specimens. 
Collected by— 
211 
2768 
3 
Adult. 
Monterey, Cal_ 
1855 
Lt. W. P. Trowbridge. 
Alcoholic. 
Lieut. Trowbridge ... 
MYLOPHARODON, Ayres. 
Gen. Char.— --Head sub-conical and tapering. Snout overlapping the lower jaw. Mouth rather deeply cleft, with its'gape 
horizontal ; no maxillar barbel. The eyo is small or moderate. The isthmus is narrow. Body elongated, subfusiform, com¬ 
pressed. Pectoral fins smaller than the ventrals, the latter being inserted in advance of the anterior margin of the dorsal. 
Caudal fin furcated. The scales are rather small, exhibiting radiating furrows upon their posterior section only; the lateral line 
running below the middle of the flanks. The teeth are disposed upon an external deciduous row of two or three, and two 
permanent rows of two and four or five, thus : 2 | 2 | 5—5 | 2 ] 2, or 3 | 2 | 4—4 | 2 | 3. The crown is quite compressed. 
Syn.— Mylopliarodon, Ayres, in Proc. Cal. Acad. Nat. Sc. I, 1855, 35.— Grd. in Proc.Acad. Nat. Sc. Philad. VIII. 
1856, 169. 
This genus is most closely related to Mylocheilus. The species which it includes are remark¬ 
able for their elongated body, their sub-conical and tapering head, their deeply-cleft mouth ; 
the ventrals being inserted in advance of the anterior margin of the dorsal, the caudal furcated, 
and the isthmus narrow. But Mylopliarodon has no barbels upon either maxillaries or the 
angle of the mouth. The pharyngeal bones are likewise stoutish, but the inferior limb is more 
elongated than in Mylocheilus , though a little smaller than the upper limb. We observe the 
same system of dentition ; but the crown of the teeth is much more compressed than in 
Mylocheilus. 
