SILVER-JAWED MINNOW. 855 
76. ERricyMBA BUCCATA Cope. 
Silver-jawed Minnow. 
Ericymba buccata, Corr, Proc. Acad. Nat. Sci. Phila., 1865, 88—GUNTHER, Cat. Fishes 
Brit. Mus., viii JORDAN, Man. Vert., 2d Ed., 299. 
Description.—Body fusiform, rather elongate, little compressed, the back not elevated ; 
head rather long, somewhat depressed above, with broad and prominent muzz!e ; mouth 
rather small, horizontal, subinferior, the lower jaw considerably shorter than upper; 
upper lip below level of pupil; maxillary not reaching to eye; dentary bones dilated, 
the macous channels conspicuous cross lines; opercle small; eye large, four in head; 
fins small, dorsal over ventrals ; scales moderate, the lateral line nearly straight ; mid- 
dle of the belly ssaleless; fifteen scales before dorsal; color olivaceous, rather pale; 
sides bright silver with bluish reflections; a dark dorsal streak, conspicuous posteriorly ; 
fins plain; males without tubercles or bright colors; head 3 5-6; depth 5; D. 8; A. 8; 
scales 5-33-3 ; teeth 1, 4-4, 0. Length 5 inches. 
Habitat, Ohio Valley. 
Diagnosis.—This species is knowa at once from all other minnows by 
the cavernous condition of the bones of the lower jaw. 
Habits.—This graceful and interesting little fish is abundant in most 
streams tributary tothe Ohio. It prefers clear, gravelly or sandy streams, 
and often ascends the small brooks. Most specimens seen are small. 
The males do not undergo any special changes in color or form in the 
breeding season. ; 
GENUs 37. PHENACOBIUS. Cope. 
Phenacobius, Copg, Proc. Acad. Nat. Sci. Phila., 1867, 96. 
Sarcidium, Corn, Hayden’s Geol. Surv., 1870, 1872, 440. 
Type, Phenacobius teretulus, Cope. 
Etymology, pkenax, deception ; bios, life, the species having the appearance of herbiv- 
orous minnows, but with the teeth and intestines of the carnivorous, 
Body elongate, subterete; mouth small, inferior, with thickened lips, the lip of the 
lower jaw developed as a conspicuous lobe on either side, presenting a slight resemblance 
to the lower jaw of Exoglossum ; no barbels; premaxillaries protractile ; dorsal fin in- 
serted in advance of ventrals; anal basis short; intestinal canal not elongated, peri- 
toneum pale; teeth 4.4, hooked, without grinding surface; scales rather small; lateral 
line continuous. Species of rather small size, bearing a considerable resemblance to 
young suckers. Three or four species are known, mostly of southern distribution. 
77. PHENACOBIUS TERETULUS Cope. 
Phenacobius teretulus, Cops, Proc. Acad. Nat. Sci. Phila., 1667, 96.—JoRDAN, Man. Vert., 
2d Ed., 299. 
Sarcidium scopiferum, Cops, Hayden’s Geol. Surv. Terr., 1872, 440 (probably same). 
Phenacobius scopiferus, JORDAN, Man. Vert., 2d Ed., 1878, 299; Bull. Hayden’s Geol. Surv. 
Terr, 1878; Bull. Ills State Lab. Nat. Hist., ii, 1878, 61. 
Phenacobius teretulus, var. liosternus, NELSON, Bull. Ills. Mus. Nat. Hist., i, 1876, 46. 
