EASTMAN: FOSSIL LEPIDOSTEIDS. 69 
gar ever brought to light. It lacks any positively archaic features and 
bears close resemblance to living forms. It is obviously the direct 
progenitor of the modern Alligator gar, Z. tristechus (Bloch and 
Schneider), and compares with it very favorably both in size and general 
characters. But if we inquire into the more remote or pre-Eocene history 
of Lepidosteids, paleeontology gives us no answer. They blossom forth 
suddenly and fully differentiated at the dawn of the Tertiary without 
the least clue to their ancestry, unheralded and unaccompanied by any 
intermediate forms ; and they have remained essentially unchanged ever 
since. 
Lepidosteus atrox Lerpy. 
Plate 1, Fig. 2; Plate 2. 
1873. Lepidosteus atror Leidy, Proc. Acad. Nat. Sci. Phil., p78. 
1873. Lepidosteus atroxr Leidy, Rept. U. S. Geol. Surv. Territ., Vol. I, p. 189, 
Plate XXXII, Figs. 14,15. (Vertebre.) 
1873. Clastes atroxr Cope, Amn. Rept. U. S. Geol, Surv. Territ., 1872, p 634. 
1873. Clastes anax Cope, loc. cit., p. 659. 
1884. Clastes atror Cope, Rept. U. S. Geol. Surv. Territ., Vol. III, p. 54, Plate IT, 
Figs. 1-24. 
1884. Clastes anax Cope, loc. cit., p. 53, Plate IJ, Figs. 50-52. (Cranial bones.) 
1900. Lepidosteus atror Eastman, Geol. Mag. [4], Vol. VII, p. 57 
Definition. — A large species, equalling the recent Alligator gar in size and 
resembling it in general characters. Head contained about four times in total 
length; snout short and broad. External bones very heavy, ornamented with 
ramifying lines of ganoine tubercles which become consolidated into more or 
less radiating ridges on the operculum and suboperculum. Jaws with an outer 
series of numerous small teeth followed by a single series of large, regularly 
spaced, conical, striated teeth implanted vertically in a rather deep and narrow 
furrow. Dorsal and anal fins remote, nearly opposed ; caudal only slightly 
convex; pelvic situated about midway between the pectorals and anal. Dorsal 
fin-rays 8, caudal 12, anal 8, pelvic 6. Fulcra biserial and prominent on all 
fins. Scales very robust, in 18-20 longitudinal series, and between 50 and 60 
oblique transverse series counting along the lateral line. Surface of scales 
smooth or with feeble ornamentation, consisting of pittings and papille; 
posterior margin fimbriate, especially so in scales of abdominal region. 
Post-clavicular scales prominently sculptured. 
Preservation. — Except for the head, the specimen is very well preserved, 
and the fin-rays remarkably so. Two thirds of the fish, including the head, lies 
squarely on the ventral surface, but in the abdominal region the body is 
twisted, so that the right lateral aspect is exposed from the tip of the tail to a 
point midway between the anal and pelvic fins. The squamation is somewhat 
