74 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Lepidosteus simplex Lerpy. 
Plate 1, Fig. 1. 
1875. Lepidosteus simplex Leidy, Proc. Acad. Nat. Sci. Phil., p. 73. 
1873. Lepidosteus simplex Leidy, Rept. U. S. Geol. Surv. Territ., Vol. 1, p. 191, 
Pl. XXXII, Figs. 18, 26, 31-43. (Vertebre, jaw-fragments, scales.) 
For the opportunity of describing this interesting specimen the writer is 
indebted to Mr. F. A. Lucas, who obtained possession of it in behalf of the 
United States National Museum after it had passed into oblivion since being 
exhibited by a private collector at the Chicago World’s Fair. It was ice 
originally at the typical Green River tess Wyoming, and bears the 
catalogue number 4754. 
The specific determination is based principally on scale characters, the 
enamel surface of the few detached scales known to Leidy being described by 
him as “ flat, smooth, and highly polished, and exhibits no markings except 
one or several minute puncte near the centre.”” One peculiar scale, which we 
can now recognize as belonging to the lateral line and oriented in a wrong 
position in Plate XXXII, Figure 33, of Leidy’s Monograph, is described (Rept. 
U.S. Geol. Surv. Territ., Vol. I, p. 191) as “traversed fore and aft by a canal 
communicating by a short cleft with the outer surface. The cleft is directed 
backward, and is protected by an angular elevation of the anterior border.” 
It would appear to be characteristic of this species that scales of the lateral line 
are traversed by short vertical canals instead of horizontal clefts, and the 
remaining scales are flat, smooth, and polished with entire edges. Other dis- - 
tinguishing features will be noted presently, and the definition may be emended 
as follows : — 
Definition. — A species attaining a total length of about 65 em., of which 
the head forms one fourth. External bones not especially heavy, arranged as 
in the recent Alligator gar, but with finer and more granular ornamentation ; 
the ganoine tubercles of operculum and suboperculum forming more or less 
continuous lines, as in L. atrox, but those of the interoperculum fused into 
irregular ridges. Jaws with an outer series of numerous small teeth followed 
by a single series of larger ones, the latter, however, relatively of much less 
size than in L. atroc. Vomers dentigerous, but no teeth observed on either 
palatines or parasphenoid. Fins as in ZL. atrox, but relatively weaker, and 
dorsal and anal more remote. Scales smooth and highly polished, with entire 
margins and no ornamentation save for occasional minute puncte near the 
centre; scales of the lateral line cleft by a short vertical canal. At least 45 
oblique transverse scale-series, and 18 to 20 longitudinal ones. Flank-scales 
of posterior part of the body considerably elongated in an antero-posterior 
direction. 
Description. —-The total length of the fish when straightened out was probably 
not far from 64 or 65 cm., or exactly four times the length of the head in the 
median line. In LZ. atroz and L. tropicus the head is also contained four times 
