ACriNOPIERTGII. 
Ohirocentrites vexillifer, J. J. Heckel, loc. cit. vol. si. ( 1856 }’ 
p. 245, pi. ii. fig S . 2 . Thrissops vexillifer , F. Bassam> 
he. cit. 1882, p. 257 ; D. G. Kramberger, Djela -T ugosia . 
Akad. vol. xvi. (1895), p. 36, pi. viii. fig. 6.— Ibid- 
Nothing is known of the so-called Chirocentriiet ? cavolin* f' r0 ® 
the Cretaceous of Pietraroja (0. G. Costa, Atti It. Accad. Sci. Nap 0 ’ 
vol. ii. 1865, no. 16, p. 9, name only). 
Genus PORTHEUS, Cope. 
[Proc. Amer. Phil. Hoe. vol. xii. 1872, p. 331.] 
Syn. Megalodon, L. Agassiz (non Sowerby, 1829), Poiss. Foss., F eui11 
1835, p. 53 (in part). , , j D 
Ilypsodon, I,. Agassiz, Poiss. Foss., Feuill. 1837, P- I 
part). _ l2 
Xiphactinus, J. Leidy, Proc. Acad. Nat. Sci. Philad. 1870, P- ^ 
A provisional name given to fragmentary remains of a 
fishes, which has not yet been clearly distinguished from O’ 
centntes. Hupraoccipital bone bearing a conspicuous 1 , 
longitudinal crest ; premaxillae short and deep. Teeth con 
exclusively to the premaxillary, maxillary, and dentary bones. ^ 
hollow, subcylindric or moderately compressed, but desfi tut ® 
sharp or serrated edges, and lodged in deep sockets ; very i" 0 *’ d 
in size, those of the premaxilla, middle of maxilla, and anterior . 
ot‘ dentary relatively large. Successional teeth formed 11 
beneath the functional teeth, and no nutritive foramina , 
inner face of the jaw below the alveolar border. All the vert 0 
centra, except a few immediately behind the head, exhibiting ^ 
deep, longitudinally-extended pits on each side. Both pa ire “ d 
with few broad and stout rays, which are very finely articulate 
divided quite at the distal end. ' Sa y ( 
A otes on the osteology of this genus are published by C. F- 
ZooL Bulh voL ii- (1898), pp. 25-54, figs. 1-16. 
Portheus molossus, Cope. . 
(?) 1870. Xiphactinus audax, J. Leidy, Proc. Acad. Nat. Sci. 
P; [Fin-ray; National Museum, Washington.] ., g 0 c. 
(?) 1871. Saurocephalm audax, E. D. Cope, Proc. Amer. I" 1 ' 
vol. xi. p. 533. 
' \ nu>l °esus, E. 1). Cope, ibid. vol. xii. pp. I 75 ’ ; 533 ' w ftU n» 
(• ) / 3. Xiphactinus audax, J, Leidy, Contrib. Extinct A er *" £>t)0, 
\V. Territ. (Rep. U.S. Geoi. Surv. Territ. vol. i. P‘- h >’ P ' 
pi. xvii. figs. 9, 10. 
