48 
ACTINOPTEEYGII. 
certainty. The postfrontal or sphenotic projects a 
little on each side and can be seen from above. Remains 
of the eheek-plates (s.o.) on both sides are very delicate, 
and exhibit the characteristic radiating markings. The 
jaws are too imperfect for description, but one of the cha¬ 
racteristic hinder mandibular teeth is seen. The opercu¬ 
lum, though fragmentary, is shown to have been deeper 
than broad ; while the preopercnlum, must clearly have 
been very little expanded at its angle. Of the gnlar plate 
only the hinder end is preserved. Egerton Coll. 
Genus SPANIODON, Pictet. 
[Poiss. Foss. Mt. Lihan, 1850, p. 33.] 
Syn, Lewisia, J. W. Davis, Trans. Roy. Dublin Soc. [2] vol. hi. 1887, 
p. 593. ^ ^ . 
Trunk elongated and laterally compressed, abdomen trenchant. 
Cheek-plates robust, exhibiting radiating branches from the slime- 
canal; jaws toothless, except the anterior end of the mandible, 
which bears one or two pairs of large conical teeth. Rranchio- 
stegal rays at least 15 in number. Vertebral centra strengthened 
by a few longitudinal ridges ; ribs very delicate and nearly straight. 
Pectoral fins large and pelvic fins smaller, these opposed to the 
hinder end of the dorsal or slightly behind it; anal fin remote, 
small and not much extended ; caudal fin deejjly forked. 17o 
enlarged scale at the base of the paired fins; no enlarged ridge- 
scales. 
The skeleton of this fish is so delicate that it is usually distorted 
in the fossils. It is thus very difiicult to distinguish the species, 
which seem to differ from each other only in their general propor¬ 
tions and in the relative length of the vertebral centra. 
Spaniodon blondeli, Pictet. 
[Text-figure 4.] 
1850. Spaniodon hlondelii, F. J. Pictet, Poiss. Foss. Mt. Liban, p. 34, 
pi. V. figs. 2-4. 
1887. Spaniodon blondelii, J. W. Davis, Trans. Roy. Dublin Soc. [2] 
vol. iii. p. 587, pi. xxxiv. fig. 3. 
(?) 1887. Spaniodon electus, J. W. Davis, ibid. p. 589, pi. xxxiv. fig. 2. 
[Nearly complete fish ; Edinburgh Museum.] 
Type. Imperfect fish ; Geneva Museum. 
The type species, attaining a length of about 0-2. The maximum 
depth of the trunk equals about two thirds of the length of the 
