Pisces. ] UPPER PALAOZOIC VERTEBRATA. 605 
SECT. XI.—VERTEBRATA OF UPPER PALAOZOIC ROCKS (Carboniferous and Permian). 
4th Sub-kingdom. VERTEBRATA. Sce page 575. 
Ist Class. PISCES. See page 575. 
4th Order. GanorpEA. See page 579. 
Ist Family. LEPIDOIDEA. 
Teeth very minute, and in numerous rows én brosse, or obtuse and in one row. Scales flat, rhomboidal, 
of moderately large size. Skeleton bony. Ventral fins near the middle of the body ; tai/ small. 
These are all rather clumsy fishes, with moderate-sized fins. They are united with the Sawroidea by 
Miiller. All the examples are extinct. There are two groups; first, with heterocercal tails, confined, with 
one exception (Coccolepis), to the Paleozoic Rocks, and of which the following genus, Paleoniscus, is an 
example. Second, with homocereal tails, confined to the Mesozoic and Tertiary rocks. 
Genus. PALASONISCUS (de Blaine. extended by Ag.) 
Syn. = (Palwoniscus + Paleothrissum) De Blainv. 
Gen. Char.—Size moderate or small, body fusiform, deep between the ventral and pectoral fins; tail 
heterocereal, forked, large, upper lobe longer and narrower than the lower, with the body extending to its 
extremity. Fins rather small, particularly the pectorals and ventrals, none of them reaching to the origin of 
the next behind; but all with strong fulcral scales. Anal fin commonly smaller than the dorsal, which latter 
occupies the space over the origins of the ventral and anal fins. The jaws are large, but the teeth en 
brosse so minute as to be scarcely visible; the muzzle projecting beyond the jaws from an expansion of the 
pre-frontal and nasal bones. Scales moderate, rhomboidal, smooth or finely striated longitudinally. 
The species with small scales are more slender than those with large ones. In some of the species 
(e.g. P. Blainvillei and P. Voltzi) the fins are covered with rows of scales, each of which rest on two 
adjacent rays, so that when removed, the impressions of the mesial articulating ridge alternates with the 
impressions of each true fin-ray,—there is no scaly covering to the fin-rays of Amblypterus, nor in other 
species of Paleoniscus (e.g. P. Freieslebeni), in which however the ordinary scales seem gradually to change 
into the articulated rays. 
Very common in the Carboniferous, Permian, and Triassic formations. 
PALMONISCUS ELEGANS (Sedgwick Sp.) 
Ref. and Syn. = Paleothrissum elegans Sedgwick, Geol. Trans. 2nd Series, Vol. III. t. 9. f. 1.=Palaoniseus elegans 
Ag. P. F. Vol. II. t. 106. f. 4, 5. 
Dese.—General form elongate-lanceolate, scarcely varying in depth from the nape to end of dorsal fin ; 
head small, semielliptical, a little less than one-fourth of the entire length to extremity of tail, its length 
