1870.] 47 5 [Cope. 
follow also. Its characters are very similar; our specimen differs in its 
more numerous scale series, a point in which the Pt. erythrurus agrees 
with all the other species with scarce an exception. I do not know of 
any genus where the number of scales is so similar in all the species, as 
in Ptychostomus. Scales 7—46—5, in a larger specimen, in a smaller they 
are 6—44—5. The cranium, however, presents us with the oblique super- 
opercular region and elevated vertex with a ridge on each side, as in the 
Pi. macrolepidotus. The premaxillary spines and nasal cartilage also pro- 
jects, leaving quite a depression across the muzzle in front of the nares, 
a feature not seen in Pt. erythrurus, and less marked in Pt. macrolepidotus. 
The mouth is quite inferior, but is large and the lips large and thick. 
The inferior has a slightly concave posterior margin, and the median pos- 
terior fissure is stronger than the others. The orbit is smaller than in 
Pt. macrolepidotus, and enters the interorbital space twice. Depth 3.75 
times in length. The dorsal outline is gently arched, and reaches its high- 
est point a little in advance of the dorsal fin. The latter has the superior 
outline but little concave, rays XII in the larger, XIII in the smaller; V. 9. 
The scales of this species are as in Pt. erythrurus, not black at base; a 
trace is seen in the smaller specimen. This mark is seen in Pt. macro- 
lepidotus and Pt. crassilabris, the latter also from the Neuse river. The 
fins are white. 
This species reaches a length of eighteen inches. One like it is sold in 
the market of the city of Newbern, N. C., with a second species much 
resembling the P¢. crassilabris, but whether identical or not, I cannot be 
sure, as my specimens were lost. 
Ptychostomus macrolepidotus. Lesueur. 
Agassiz in Sillim. Amer. Journ. Sci., Arts XIX. 89, Catostomus macro- 
lepidotus, Les. Journ. Acad. Natl. Sciences, I, 1817, 94 Tab. 
Fusiform compressed, the depth entering the length 34 times; the head 
short, contracted anteriorly, the occipital region elevated, very convex 
transversely. Length of head 4.6 to 4.5 times in length; orbit large, 
diameter 4 to 4.3 times in length of head, and twice in interorbital width. 
Scales 5—45—5, radii D. XIII; V. 9. The lips are well developed, and 
the posterior is transverse posteriorly. 
The length of the specimen described is about a foot. The color in 
life including fins, is white, yellow shaded above. 
Ten specimens have been compared, all from Pennsylvania and Dela- 
ware. Of five from the Conestoga Creek, a tributary of the Susquehanna, 
two have the parietal, median frontal, and nasal bony ridges very promi- 
nent, while in two they are almost without trace. In the former the 
dorsal radii are XIII, in the latter XII. I cannot discover the sexes of 
these specimens as they have been eviscerated. In the other five there are 
several with weak crests, but none with XII D. rays. 
In a large specimen from the Wabash River, the only departure from 
the typical form is the more emarginate inferior lip. 
This species is especially abundant in the comparatively sluggish streams 
