44 PALEOZOIC FISHES OF NORTH AMERICA. 
enameled coating of the cranial plates is wanting, and we cannot make a 
detailed comparison with our species. 
Recently I had an opportunity of seeing another specimen of Macrope- 
talichthys in Berlin, where it was exhibited with other Devonian fishes found 
by Prof. A. von Koenen in Devonian strata near Gottingen. This is 
remarkably like our species M. Sullivanti, but is smaller and different in the 
ornamentation of the cranial plates. In our species they are closely set 
with stellate enameled tubercles, but in von Koenen’s specimen the tuber- 
cles coalesce, running into convoluted parallel lines like the ornamentation 
of Pterichthys and Acanthaspis. 
Genus ASTEROSTEUS, Newb. 
Of this fish the cranium only is known, and of this all the specimens 
yet obtained are incomplete. The head was apparently long and narrow, 
the sides nearly straight, broadening suddenly in the occipital region. The 
posterior margin of the cranium shows two broad arches—one on either side 
of the main line—in which the cranial bones are deeply excavated, as though 
for muscular attachment. The skull is terminated behind by two conspicu- 
ous rounded projections, having the aspect of condyles, but which, so far as 
can be seen, show no articulating faces. The upper surface of the cranium 
is covered with relatively large, beautifully stellate tubercles, which vary 
considerably in size. Toward the nasal extremity are two linear furrows, 
which diverge from the middle line of the cranium and inclose two strongly 
marked elliptical pits that closely resemble the nostrils of some reptiles. 
In none of the specimens of this peculiar fish yet obtained have the out- 
lines of the cranial plates been distinguishable, the surface being covered 
by a sheet of tuberculated enamel, by which the sutures are entirely con- 
cealed. On the sides the cranium is somewhat beveled off, as though for 
the attachment of some coriaceous or ligamentous appendage, or perhaps 
for co-adaptation to lateral head plates ; none of which have, however, been 
found. The dentition of Asterosteus is quite unknown, as no jaws or teeth 
have been discovered with its remains. 
