﻿342 CROSSOPTERYGII. 



Genus RHIZODUS, Owen. 

 [Odontography, 1840, p. 75.] 



Syn. Megalichthys, L. Agassiz & S. Hibbert, Trans. Roy. Soc. 

 Edinb. vol. viii. 1836, p. 202 (non Megalichthys, L. Agassiz, 

 1844 : see p. 378). 



The typical genus, imperfectly known, comprising species of very 

 large size. Infraclavicle with a long, slender, upwardly-directed 

 process. External bones and scales superficially ornamented with 

 tubercles, ridges, or reticulations of ganoine. Crown of teeth 

 smooth, compressed to a sharp edge anteriorly and posteriorly. 

 No ossified vertebrae. 



So far as known, the genus Rhizodus is confined to the Lower 

 Carboniferous, and its remains are very fragmentary. Of the fins, 

 only the lobate pectoral has been discovered l . 



Rhizodus hibberti (Agassiz & Hibbert). 



[Plate XII. figs. 1-4.] 



1793. " Fishes' Teeth," D. Ure, Hist. Rutherglen & Kilbride, p. 330, 

 pi. xix. figs. 4, 6. 



1836. Megalichthys hibberti, Agassiz & Hibbert, Trans. Roy. Soc. 

 Edinb. vol. xiii. p. 202, pi. viii. fig. 1 {non fig. 2), pi. ix. figs. 2, 3, 

 9, 10 ; woodc. on p. 183. 



1837. Megalichthys hibberti, W. Buckland, Geol. & Mineral, ed. 2 

 vol. ii. p. 43, pi. xxvii. fig. 12. 



1837. Holoptychus hibberti, W. Buckland, ibid. p. 43, pi. xxvii. figs. 



9-11, 13, 14. 

 1841. Rhizodus hibbertii, R. Owen, Odontogr. vol. i. p. 75, vol. ii. p. 12, 



pi. xxxv. fig. 2, pis. xxxvi., xxxvii. 

 1844. Holoptychius hibberti, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. p. 180 



(name only). 

 (?) 1843. Phyllolepis tenuissimus, L. Agassiz, ibid. p. 180 (name only). 

 1855. Rhizodus hibbeHi, F. M'Coy, Brit. Pakeoz. Foss. p. 612. 

 1855. Rhizodus gracilis, F. M'Coy, ibid. p. 611, pi. iii. g. rig. 17. 



[Dentary ; Woodwardian Museum, Cambridge.] 



1865. Rhizodus hibberti, J. Young, Trans. Geol. Soc. Glasgow, vol. ii. 

 p. 38. 



1866. Rhizodus, J. Young, Quart. Journ. Geol. Soc. vol. xxii. p. 599 

 (except scales). 



1876. Rhizodus, W. J. Barkas, Monthly Review Dental Surgery, vol. iv. 

 p. 394, figs, lxxx., lxxxi. 



1 R. H. Traquair, Ann. Mag Nat. Hist. [4] vol. xv. 1875, p. 267. 



