72 TRIASSIC FISHES AND: PLANTS. 
suddenly as it came, leaving among the Tertiary and living fishes no de- 
scendants which can be affiliated with it. In the description of Calacanthus 
elegans’ I have referred to the close resemblance and possible identity of 
this little fresh-water fish with C. leptwrus, which lived in the lagoons in the 
coal marshes of England. Not only are all details of internal structure the 
same, but the elaborate ornamentation of scales and head plates presents no 
tangible differences. 
From Holophagus (with which Diplurus seems to be most closely allied) 
its only obvious differences are the finer striation of the scales, the wider 
separation of the two caudal fins, and the fewer articulations of the fin 
rays. In Holophagus and Undinaand in the Jurassic species of Celacanthus 
described by T. C. Winkler? the supplemental caudal fin seems to spring 
directly from the extremity of the caudal. In Diplurus there is a distinet 
interval between them; a character which suggested the name Diplurus, or 
double-tail. Judging from the specimens of Holophagus gulo which I re- 
cently had an opportunity of examining, both the original of Sir Philip 
Egerton’s generic description and the more complete one figured by Pro- 
fessor Huxley,’ I should say that this was a shorter and broader fish than 
our Diplurus. Sir Philip Egerton’s specimen is much smaller, but it wants 
the head, and can not be fully compared. In the body traces of another 
fish are visible, which had apparently been swallowed. This would show 
that Holophagus was carnivorous. The scales of Holophagus are orna- 
mented with relatively few short, broad, divergent ridges of enamel, while 
our species of Diplurus has many fine parallel thread lines on the scales. 
In my description of the first specimens of Diplurus found IT reported 
the fin rays to be smooth and the scales granulated, but that specimen 
was from Boonton, N. J., and was buried in a coarse, sandy shale, in which 
the minute spines of the fin rays were not discernible, and the thread lines 
of the scales were broken into granules by the grains of sand. Other 
and better specimens found later at Durham, Conn., show the characters 
now described. 
1 Rept. Geol. Survey Ohio, vol. 1, pt. 2, Paleontology, 1873, p. 339. 
2 Archives Musée Teyler, vol. 3, pp. 101-116. 
3Mem. Geol. Survey United Kingdom, British Organie Remains, Decade 13, 1872. 
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