EASTMAN: FOSSIL LEPIDOSTEIDS. 73 
Regarding the fine head of Lepidosteus atrox (Plate 2) procured by Mr. 
Charles Schuchert for the United States National Museum while collecting in 
Wyoming last summer, Mr. Lucas writes : — 
“The specimen (Cat. No, 4755) consists of a little more than the anterior 
half of an individual of about the same size as that belonging to the Museum 
of Comparative Zoology at Cambridge. It lies upon the ventral surface, and 
while the body has of course been flattened, the cranium has suffered but little 
from compression, and is almost as favorable for study as a fresh gar would be. 
“The general form of the cranium is intermediate between that of Lepidos- 
teus osseus and L, tristechus, the muzzle being slightly wider than in the first- 
named and narrower than in the latter, so that there is no such obvious notch 
towards the anterior part of the ethmonasals as appears in L. tristechus. At 
the same time the back of the cranium is proportionately wider in the Eocene 
than in the living species, the result being that the skull of L. atrox tapers 
somewhat abruptly from behind forward. 
“The right vomer is turned outwards exposing its anterior end, and a frac- 
ture across the muzzle brings to view a section of the palatines ; from these 
exposures it is possible to state that both vomers and palatines are dentigerous, 
while in the lower jaw teeth are visible on the dentary. There is no apparent 
difference between the dentition of L. tristechus and L. atrox save that in the 
present specimen none of the teeth are so large as in the living species. The 
Cambridge example, however, shows this to be an individual peculiarity. Two 
nasal plates are present on either side as in existing gars, and the maxillary 
segments are seven in number, or one more than in the two examples of the 
Alligator gar available for comparison. The ethmonasals, especially the ex- 
ternal sculptured parts, are, as previously noted, narrower in L. atrox than in 
L. tristechus. The frontals are much the same in the two species, but the 
parietals and squamosals are a little shorter and wider in the fossil than in the 
living gar. The circumorbitals are displaced and few of them visible, but such 
as can be seen are notably thick. The same remark applies to the operculum 
and suboperculum, for although of practically the same size as in L. tristechus, 
they are decidedly thicker. The cranial bones ate also heavy, and their sculp- 
turing while well defined is a trifle finer and decidedly more granular.” 
PrincipAL MEASUREMENTS OF THE WASHINGTON Cranium (cf. Plate 2). 
Length from extreme tip of nasals to end of supratemporals . . . . 34.2 cm. 
Length of maxillary 4% o 6 6 6 6 6 Bo TURE 
Length of exposed portion of Dhnronaaal along Aine Bec rrn Camcums (1a) 
Length of frontals along median suture ........... .. 137 
lbengthvot parictalsyalongmediansuture 9.9... <<... . +. 46 
Waidtivacross anterior part of. ethmonasal 29.6294 «5°. 2... sO 
Width across exposed portion ofethmonasal . ........ =. «22 
Maximum width across anterior portion of both frontals . . .. . . 5. 
Maximum width across posterior portion of both frontals, at junction 
with squamosals .. . oS 
Maximum width between outer borders of niet ee left “quem elas 
