BELONORHYNCHIDAE 



321 



No scales occur on the body, but generally a dorsal, a ventral, and two 

 lateral longitudinal rows of scutes. The fulcra are vestigial or absent. 



A. 



FIG. 301. 



Belonorhynchus. (After A. S Woodward.) 



The notochord was persistent. There are no centra, but well-developed 

 bony ribs, haemal and neural arches and spines. As in the higher 

 Holostei, the neural arches bear articulating zygapophyses. This most 

 puzzling assemblage of characters 

 has not yet been satisfactorily 

 explained. 



Belonorhynchus, Bronn (Fig. 

 301); Trias, N.S. Wales; Juras- 

 sic, Europe. SaurichtJiys, Ag. ; 

 Trias, Europe. ? Saurorhamphus, 

 Heckel ; Cretaceous, Europe. 



Subdivision 2. HOLOSTEI. 



The three sub-orders in- 

 cluded in this subdivision 

 belong to a higher grade of 

 organisation than the fish we 

 have hitherto dealt with. 

 They have certain characters 

 in common which at once 

 distinguish them. The endo- 

 skeleton is very thoroughly 

 ossified. In the anal and 

 dorsal fins the lepidotrichia 

 correspond in number to the 

 radials. In the caudal fin of 

 the Amioidei and Lepido- 

 steoidei the correspondence is 

 incomplete, and in the caudal 

 of the Teleostei the dermal 



Fia. 301 A. 



lucius, L. A, two radials of the dorsal flu, 

 left-side view. B, radial and dermal ray from in 



i 



haemal 



Still greatly exceed the front, d, distal cartilage ; m, median segment, and 

 i i i p.r, proximal segment of radial ; I, lepidotricli, 



al arches in number broken short in A! 



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