A treatise on zoology . 237Z2ZZ337Z7 y>i. -^ Fio. 301. Ldonorhyiwlius. (After A. S Woodward.) The notochord was persistent. There are no centra, but well-developedbony ribs, haemal and neural arches and spines. As in the higherHolostei, the neural arches bear articulating zygapophyses. This mostpuzzling assemblage of charactershas not yet been Jlelonorhynclbiis, Bronn ); Trias, Wales; Juras-sic, Europe. SauricJdhijs, Ag. ;Trias, Europe. 1 Saurorhavijihus,Meckel; Cretaceous, Europe. Subdivision 2. HOLOSTEI. The three sub-orders in-cluded in this subdivi
A treatise on zoology . 237Z2ZZ337Z7 y>i. -^ Fio. 301. Ldonorhyiwlius. (After A. S Woodward.) The notochord was persistent. There are no centra, but well-developedbony ribs, haemal and neural arches and spines. As in the higherHolostei, the neural arches bear articulating zygapophyses. This mostpuzzling assemblage of charactershas not yet been Jlelonorhynclbiis, Bronn ); Trias, Wales; Juras-sic, Europe. SauricJdhijs, Ag. ;Trias, Europe. 1 Saurorhavijihus,Meckel; Cretaceous, Europe. Subdivision 2. HOLOSTEI. The three sub-orders in-cluded in this subdivisionlielong to a higher grade oforganisation than the fish wehave hithei^to dealt have certain charactersin common which at oncedistinguish them. The endo-skeleton is very thoroughlyossified. In the anal anddorsal fins the lepidotrichiacorrespond in number to theradials. In the caudal fin ofthe Amioidei and Lepido-steoidei the correspondence isincomplete, and in the caudalof the Teleostei the dermal. Fig. 301a. Ksox bwius, L. A, two radials of the dorsal fin,.,, , 1 ^, left-side view. B, radial and dermal ray from in rays still greatly exceed the front, a, distal cartilage ; m, median segment, and haemal arches in number ^^^T^inT °^ ?^ = lepidotrich. 322 HOLOSTEI (Figs. 62-3). The lepidotrichia can be erected aud depressed in allthe fins except the caudal (Fig. 301 a). The median radials pro-ject not at all beyond the level of the body-wall, and are composedof three-jointed rods as a rule ; the proximal segment is long (inter-spinous bone), the two distal segments short, the outer one beingrigidly fixed in the bifurcated base of the lepidotrich. The tailis abbreviate heterocercal, homocercal, or of some more modifiedtype (p. 353); but the hinder end of the iipper lobe of the hetero-cercal tail of the larva (the axial lobe) is always lost during
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