256 FOSSIL FISHES OF THE ENGLISH CHALK. 



Tertiary period, except that of the Pycnodonts, which is occasionally found until 

 the Upper Eocene, and possibly that of the Polyodontidse, which is only doubtfully 

 represented in the Chalk. They are, indeed, essentially Jurassic groups whose 

 last specialised members are lingering- just before their extinction. Belonostomus 

 attains its maximum size, most powerful dentition, and most extensively ossified 

 vertebras. It also has a very wide distribution, being found not only from the 

 Neocomian to the Senonian in Europe, but also occurring in North America, 1 

 Brazil, 2 and Australia. 3 Protosphyraena is the largest and latest Pachycormid, 

 with the longest and most powerful rostrum, and the largest and strongest teeth ; 

 as common in the Upper Cretaceous of North America as in that of Europe, 

 and known also by teeth from Patagonia. 1 Lophiostomus is a Eugnathid, but the 

 bony prominences on its skull indicate that it has reached the climax of its 

 race. Neorhomholepis from England, and Otomitla from Mexico, 5 have the 

 vertebrae unusually well ossified, while the fulcra have disappeared from the fins, at 

 least in the first-mentioned genus. Fishes of this type have a wide range both in 

 time and space, for Nem^hombolepls occurs in the Wealden of England as well as in 

 the Chalk ; while scales and vertebras similar to those of this genus were found by 

 Mr. Joseph Mawson and myself in 1907 in the Lower Cretaceous rocks of a railway 

 cutting near Santa Amara, in the State of Bahia, Brazil. Of the Pycnodonts, the 

 Cretaceous Anomceodus is unique in having the splenial incompletely covered with 

 teeth; the dentition of Gyrodus {?) cretacem exhibits a lack of orderly arrangement 

 which suggests senility ; while the skull and pectoral arch of Coccodns from the 

 Lebanon bear bony spinous prominences. Even Macroponui, which is the last of 

 the race of Ccelacanths, is unusually specialised in the skull and in the scale- 

 armature, and has lost the fringe of fin-rays at the end of the tail. 



Apart from the relatively large size of most species, there is nothing worthy of 

 remark in the Cretaceous Chimaeroids. The Elasmobranchs, however, are more 

 interesting, and some need special notice. Nearly complete skeletons are 

 abundant in the Upper Senonian of the Lebanon, 7 and they occasionally occur in 



1 Belonostomus ornatus, J. Felix, Palaeontographica. vol. xxxvii (1891), p. 192, pi. xxviii, figs. 

 14—18, pi. xxx, fig. 8. 



' 2 Belonostomus comptoni, A. S. Woodward, Proc. Zool. Soc, 1890, p. 629, pis. liv, lv. 



3 Belonostomus siveeti, Etheridge and Woodward, Trans. Roy. Soc. Victoria, vol. ii (1892), pt, ii, 

 p. 3, pi. i. 



i A. S. Woodward, Geol. Mag. [4], vol. iv (1897), p. 22. 



5 J. Felix, loc. elt. (1891), p. 189, pi. xxix, fig. 3, pi. xxx, figs. 3—5. 



c A. S. Woodward, Catal. Foss. Fishes Brit. Mus., pt. iii (1895), p. 266 • J. W. Davis, Quart, Journ. 

 Geol. Soc, vol. xlvi (1890), p. 565, pi. xxii. 



7 See especially F. J. Pictet, Description de quelques Poissons Fossiles du Mont Libau 

 (Geneva, 1850) ; F. J. Pictet and A. Humbert, Nouvelles Recherclies sur les Poissons Fossiles du 

 Mont Liban (Geneva, 1866) ; J. W. Davis, " The Fossil Fishes of the Chalk of Mount Lebanon in 

 Syria." Trans. Roy. Dublin Soc. [2], vol. iii (1887), p. 457; O P. Hay, Bull. Amer. Mus. Nat. Hist., 

 vol. xix (1903), art. x; also Catal. Foss. Fishes Brit, Mus., pt. i (1889). 



