90 BULLETIN OF THE 
lary reaching about half-way to the orbit. Snout bluntly rounded above the 
mouth. Dorsal somewhat larger than the anal; a vertical from the posterior 
extremity of its base passes in front of the vent. Ventrals short, not reaching 
the vent, insertion very little in advance of that of the dorsal. Pectorals rather 
small, reaching a little more than half-way to the ventrals. Caudal deeply 
notched. The lateral line descends slightly along the middle of the body. 
Back brownish ; belly whitish ; cheeks silvery. Scales punctulate with 
black. Much lighter colored than Dionda melanops Girard. A spot on the 
tail at the end of the lateral line. Distinguished from D. couchii Girard by 
the size of the scales and a stouter form. The formule for D. melanops, 
according to type sent by the Smithsonian Institution, are D. 24-8 ; A.2-+-8; 
V. 8; P. 14 ; L. lat. 42; L. trans. 6-]- 1 +4. 
Parras, and spring near Saltillo, 
STYPODON, gen. nov. 
Body oblong, compressed. Scales large, deciduous. Lateral line complete, 
below the middle of the side of the tail. Dorsal and anal fins short ; spinous 
rays weak. Mouth small, anterior ; upper jaw protractile ; fold of lower lip 
not crossing the symphysis ; lower jaw trenchant, without a horny covering. 
No barbels. Gill rakers short. Pharyngeals strong ; teeth 3 — 3, of the My- 
locheilus type, more or less cylindrical, with rounded grinding surfaces, pos- 
terior more slender and subconical. 
Stypodon signifer sp. nov. 
D. 22-8; A. 2+8; V. 8; P. 12; L lon. 35; L. trans. 6 ๆ - 1 ๆ - 2. 
Length of head or height of body three and two thirds times in the total 
length, without caudal. Body compressed, upper and lower outlines similar, 
forming a gradual curve from snout to dorsal. Head moderate, length in front 
of the eye a little less than the diameter of the orbit. Mouth oblique, lower 
jaw more prominent, upper protractile. Maxillary hardly reaching a vertical 
from the anterior margin of the orbit. Eye comparatively large. Pharyngeals 
very strong. Teeth 3 — 3, stout ; stump-like with smooth convex summits. 
The posterior tooth of each series is more slender, and the shape of its top ap- 
proaches that of a cone with rounded apex. The anvil or bone against which 
they strike is large and heavy, subelliptical in shape, and in length equals the 
diameter of the orbit. Scales moderately large, easily detached, broadly 
rounded on the posterior margin. The depth of the caudal notch is less than 
half of the free portion of the fin. Ventrals not quite reached by the pec- 
torals, reaching the anal, inserted a little in front of the first dorsal ray. Lat- 
eral line complete, below the middle of the caudal peduncle. 
Upper half of head and body. brown ; below the lateral line and eye silvery ; 
fins light colored, A broad band of dark brown from the eye to the caudal 
