﻿khizodontid^:. 355 



The superficial film of ganoine upon the scales and external bones 

 of this genus being very thin, it is usually destroyed. The scales, 

 as a rule, exhibit a few concentric markings crossed by numerous 

 very fine, radiating lines, due to the inner structural features. 



The osteology of the head and branchiostegal apparatus has been 

 described in detail by Traquair l , who gives the restorations already 

 described on p. 319 (fig. 47). 



Rhizodopsis sauroides (Williamson). 



1837. " Fossil Salmon," W. C. Williamson, Phil. Mag. [3] vol. xi. p. 300, 



pi. ii. figs. 4-6. [Scales.] 

 1841. Holoptychius, sp. nov., E. W. Binney, Trans. Manchester Geol. 



Soc. vol. i. p. 165, pi. v. fig. 6. [Dentary bones ; E. W. Binney 



Collection.] 

 1841. Holoptychius sauroides, E. W. Binney (errore), ibid. p. 165, pi. v. 



figs. 8, 10. [Scales.] 

 1844. Holoptychius granidatus, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. 



p. 180 (name only). 

 1849. Holoptychius sauroides, W. C. Williamson, Phil. Trans, p. 457, 



pi. xlii. figs. 21-23. 

 1861. JRhizodus granulatus, J. W. Salter, Foss. S. Welsh Coalfield 



(Mem. Geol. Surv. — Iron Ores Gt. Britain, pt. iii.), p. 223, pi. i. 



figs. 4-6 (also teeth, ibid. pi. i. figs. 1-3, 7-9). 

 1864. Holoptychius, sp. indet, Kirkby & Atthey, Trans. Tyneside Nat. 



Field Club, vol. vi. p. 235, pi. vi. fig. 4. 



1866. Rhizodopsis sauroides, J. Y oung, Quart. Jo urn. Geol. Soc. vol. xxii. 

 p. 596, woodc. fig. 8. 



1867. Dittodus parallelus, R. Owen, Trans. Odontol. Soc. vol. v. p. 325 

 pi. i. [Micro, section of jaw; British Museum.] 



1867. Ganolodus cragyesii, R. Owen, ibid. p. 356, woodcut. [Dentary 



bone ; British Museum.] 

 1867. Characodus confertus, R. Owen, ibid. p. 366, pi. xiii. [Micro. 



section of tooth.] 



1867. Gastrodus propositus, R. Owen, ibid. p. 370, pis. xiv., xv. [Micro. 

 section of jaw j British Museum.] 



1868. Rhizodopsis sauroides, Hancock & Atthey, Ann. Mag. Nat. Hist. 

 [4] vol. i. p. 349. 



1870. Rhizodopsis sauroides, Hancock & Atthey, Nat. Hist. Trans. 



Northumb. & Durham, vol. iii. pp. 85, 91. 

 1873. Orthognathus reticulosus, T. P. Barkas, Coal-Meas. Palaaont. 



p. 38, figs. 143, 144. [Portions of jaws; T. P. Barkas Collection.] 

 1873. Rhizodopsis, T. P. Barkas, ibid. p. 23, figs. 59-69. 

 1875. Rhizodopsis sauroides, J. Ward, [Proc] N. Staffs. Nat. Field Club 



p. 231. 



1 Trans. Koy. Soc. Edinb. vol. xxx. (1881), p. 169, woodcuts figs. 1-3 



2a2 



