470 ACTINOPTERVGII. 
'PUf-■■ . 
Genus P^GOPTJESIt.TJS, Agassiz. 
[Poiss. Poss. Yol. ii. pt. i, 1833, p. 10, and ibid, pt. ii. 1844, p. 74.] 
Trunk elongated, gradually tapering from the occiput. Mandi¬ 
bular suspensorium oblique ; dentition consisting of a series of large 
well-spaced conical teeth, and more numerous small teeth forming 
an outer series; opercular apparatus relatively small; all the head 
and opercular bones ornamented with striations. Pins well deve¬ 
loped, with fulcra, the rays flattened and unornamented, mostly 
articulated and branched. Pectoral fins having the principal rays 
unarticulated, except distally ; pelvic fins relatively small and short- 
based ; dorsal fin opposed to, or arisingjightly in advance of the 
anal, high and acuminate in front, with a scarcely elongated base¬ 
line ; anal fin much extended, high and acuminate in front, but low 
and fringe-like in its hinder half; upper caudal lobe much elongated, 
the fin deeply forked and nearly equilobate. Scales relatively small, 
thin, smooth or feebly ridged, those of the flanks of the abdominal 
region scarcely deeper than broad, and those of the ventral aspect 
not much broader than deep, except in the caudal region : the peg- 
and-socket articulation of the principal scales large and prominent. 
. t 
Pyg@pteras humboldti, Agassiz. 
1709. Figure by G. F. Mylius, Memorabilia Sari&nisc subterr. pt. i. fig. 1. 
1719. Figures by P. Wolfart, Hist, nat, Ilassise inf. pt. i. pis. xviii., xix. 
1818. Palceothrissum magnum, , IT. D. de Blainville, Nouv. Diet. d’Hist. 
Nat. vol. xxvii. p. 321. 
1818. Esox eislebensis, H. I), de Blainville, ibid. p. 322. 
1829. “Fossil fish,” A. Sedgwick, Trans. Geol. Soc. ("2] vol iii 
p. 118, pi. x. 
1833. Pygopterus humboldti, L. Agassiz, Poiss. Foss. vol. ii. pt. i. p. 10. 
ISOo. Pygopterus scoticus , L. Agassiz, ibid. p. 10 (includes undefined 
species Nemopteryx mandibularis and Sauropsis scoticus). 
1835. Pygopterus humboldti , F. A. Quenstedt, WIegmann’s Archiv, 
Naturg. vol. ii. p. 93. 
1835. Pygopterus scoticus, F. A. Quenstedt, ibid. p. 93. 
1839. Pygopterus humboldti, G. A. Kurtze, Comment. Petrefact. Mans- 
feld. p. 25. 
1840. Pygopterus humboldti, E. F. Germar, Verstein. Mansfeld. Kupfer- 
schief. p. 22. 
1842. Pygopterus humboldti, G. von Munster, Beitr. Petrefakt. pt. v. 
p. 48, pi. v. fig. 1. 
1844. Pygopterus humboldti, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. p. 74 
pis. liv., lv. 
1844. Pygopterus mandibularis, L. Agassiz, ibid. p. 76, pis. liii., liii. a. 
. ^^ x '- 
