PHAXEROPLETJRIDJS. 
247 
Genus PHANEROPLEURON, Huxley. 
[Iu Anderson’s Dura Den, 1859, p. 67.] 
Body laterally compressed, covered with very thin scales of mode¬ 
rate size ; snout acute. Marginal teeth conical; dental plates with 
ridges of well-separated conical tubercles. Paired fins acutely 
lobate ; dorsal fin single, arising in advance of the pelvic pair and 
continuous with the caudal; anal fin small, separate. 
Phaneropleuron andersoni, Huxley. 
1859. Phaneropleuron andersoni, T. H. Huxley, in J. Anderson’s Dura 
Den, p. 67, pis. v., vi. 
1861. Phaneropleuron andersoni, T. H. Huxley, Figs. & Descrips. Brit. 
Organic Remains (Mem. Geol. Suit.), dec. x. p. 47, pi. iii. 
1862. Phaneropleuron, J. Powrie, Quart. Journ. Geol. Soc. vol. xviii. 
p. 434. 
1872. Phaneropleuron andersoni, R. H. Traquair, Journ. Roy. Geol. Soc. 
Ireland, n. s. vol. iii. p. 44, woodc. 
Type. Xearly complete fish; British Museum. 
The type species, attaining a length of at least 035. Trunk 
narrow and elongated, more than four times as long as the head 
with the opercular apparatus ; tail produced and acutely pointed. 
Marginal teeth high and conical. Scales very thin, marked with 
delicate, granulated, radiating striae. 
Form. Log. Upper Old Red Sandstone: Dura Den, Fifeshire. 
Fig. 39. 
Phaneropleuron andersoni , Huxl.—Restored outline, by R. H. Traquair. 
28120. A slab of yellow sandstone with remains of several indi¬ 
viduals of Holoptycliius jlemmgi and Phaneropleuron 
andersoni, including the type specimen of the latter, de¬ 
scribed and figured in Anderson’s ‘ Dura Den,' pi. vi. fig. 2, 
and in the Mem. Geol. Surv. dec. x. pi. iii. fig. 1. One 
fish exhibits the conical marginal teeth, another apparently 
