COELACANTHINI 



2*7 



Division 2. 

 Order COELACANTHINI. 



These remarkable fisL appear first in the Devonian and persist 

 in the Cretaceous rocks. They are very uniform in structure 

 throughout this long period, and are clearly marked off from 



Fig. 259. 



Undino gulo, Eg. ; Lower Jurassic, Dorset. Restoration, omitting scales and supraclavicle 

 and allowing the calcified air-bladder. (From A. 8. Woodward, Brit. Mus. Catal.) 



related Teleostomes by well-defined characters. Huxley [228], 

 Miinster, Wellburn [484], Winkler, Willemoes-Suhm, Reis [350, 

 354], and other authors have given us a 

 very complete description of their skeleton. 

 The notochord appears to have been 

 persistent and unconstricted ; at all events, 

 no trace of centra is found. The tail is 

 diphycercal, and subdivided into three 

 lobes, of which the central one projects 

 far beyond the epi- and hypochordal lobes, 

 and has no ossified endoskeletal supports. 

 The neural arches, haemal arches, and 

 pleural ribs are well developed and ossified. 

 The arches are fused to the spines, and 

 to these are articulated in the caudal region 

 a corresponding series of somactidia or 

 radials, supporting the lepidotrichia of the 

 epi- and hypochordal fins (Fig. 259). Unlike what occurs in all 

 Teleostomes excepting the higher Actinopterygii (p. 321), these 

 lepidotrichia agree in number with the endoskeletal radials, and are 

 closely connected with them. One anal and two dorsal fins are 

 present ; they have remarkable projecting, scale-covered lobes, with 



Fro. 260. 



Ventral view of the pelvic 

 rdle and fins of HolopJiagus gulo, 

 uxley. p, pelvic bone ; pf, out- 

 le of fin. (From Quart. Journ. 



