CHIROCENTHIDiE. 
89 
47514 . Type specimen, comprising left dentary and impression of 
left maxilla. The extent of the mandibular dentition, 
which comprises 23 teeth, is 0 - 045. 
Presented hy Herr R. I). M. Verbeek, 1876. 
Genus PLATINX, Agassiz. 
[Neues Jahrb. 1835, p. 304.1 
Syn. Thrmoplerus, J. J. lleckel, Uenkschr. k. Akad. Wiss., math,- 
naturw. Cl. vol. xi. 1850, p. 245. 
Trunk elongated and laterally compressed ; abdomen trenchant. 
Teeth small and in regular close sorios in both jaws, not enlarged in 
the premaxilla. About six or seven branchiostegal rays. Vertebrae 
approximately 70 in number, nearly half being caudal ; ribs round 
in section. Pectoral fins considerably enlarged, the length of the 
rays exceeding that of the head with opercular apparatus ; pelvic 
fins very small ; dorsal fin low and much extended, opposed to the 
anal, which is also much extended but not elevated into a pointed 
lobe in front; caudal fin deeply forked. Scales large and smooth. 
The following species of this extinct genus are recognised, but are 
not represented in the Collection : — 
Platinx catullii : Thrissopterus catullii, J. J. lleckel, Denkschr. k. 
Akad. Wiss., math.-uaturw. Cl. vol. xi. (1856), p. 248, 
pi. xii. fig. 5. — Upper Eocene ; Monte Bolca, near Verona. 
[The type species of I'hrissopterus. Nearly completo fish ; 
University Museum, Padua.] 
Platinx elonyatus, I,. Agassiz, Noues Jahrb. 1835, p. 304, and 
Poiss. Foss. vol. v. pt. ii. (1835-44), p. 125, pi. xiv. ; 
F. Ii assail i, Atti Soc. Veneto-Trent. Sci. Nat. vol. iii. 
(1876), p. 188. Esox macropterus, II. 1). de Blainville, 
Nouv. Diet. d'Hist. Nat. vol. xxvii. (1818), p. 342. — Ibid. 
[The type species. Nearly complete fish ; Paris Museum 
of Natural History.] 
Platinx (jiyas, L. Agassiz, Neues Jahrb. 1835, p. 304. Monopteros 
; jiyas , G. 8. Volta, Ittiolit. Veronese (1796), p. exei, 
pi. xlvii.— Ibid. [Nearly complete fish ; Paris Museum 
of Natural History.] 
Genus CHIROM YSTUS, Cope. 
[Proc. Amer. Phil. Soc. vol. xxiii. 1886, p. 4.] 
Trunk elongated and laterally compressed. Teeth rounded in 
section and hollow, not in deep sockets but firmly fixed to the jaws ; 
