﻿RHIZODONTIDJE. 365 



thickly set with fine conioal or rounded granules, generally without 

 linear arrangement." 



The type species of this genus is S. taylori, J. Hall, Nat. Hist. 

 New York, pt. iv. Geology, 1843, p. 282, woodc. fig. 130 (1) 

 (further noticed by J. S. Newberry, Palaeoz. Fishes N. America, 

 1889, p. 112), founded upon portions of a fish from the Catskill 

 Group of Blossburgh, Pennsylvania, now in the American Museum 

 of Natural History, New York. A personal examination of the 

 original specimen has convinced the present writer (Geol. Mag. [3] 

 vol. vii. 1890, p. 392) that the arrangement of the cartilages in the 

 obtusely lobate pectoral fin and the structure of the teeth suffice to 

 determine the Rhizodont character of the fish. It may also be 

 added that the writer did not observe the external tubercular scale- 

 ornament noted by Newberry, while the reticulated markings sug- 

 gested to him the corresponding ornamentation on the exposed 

 portion of the scales of Strepsodus (see PI. XY. fig. 1). 



The two following species are only provisionally placed here 

 until the discovery of more satisfactory specimens. 



Sauripteriis favosus (Agassiz). 



1844. Glyptosteus favosus, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. p. 179 



(name only). 

 1844. Bothriolepis favosa, L. Agassiz, Poiss. Foss. V. G. R. pp. 61, 



100, pi. xxvii. fig. 7, pi. xxviii. figs. 12, 13. 

 1860. Dendrodus favosus, E. von Eichwald, Leth. Rossica, vol. i. 



p. 1561 (in part). 

 1888. Cricodus (?) favosus, R. H. Traquair, Geol. Mag. [3] vol. v. 



p. 515. 

 1890. Cricodus (?) favosus, Woodward & Sherborn, Cat. Brit. Foss. 



Yertebrata, p. 48. 



Type. Portions of jaws ; unknown. 



Laniary teeth much compressed, very broad at the base, tapering 

 to a slender, faintly recurved apex. External surface of mandible 

 coarsely tuberculated • some of the head-bones more finely marked, 

 the granulations tending towards arrangement in series. [Scales 

 and vertebras unknown.] 



The known examples of the jaws of this species are about 0*25 

 in length, and a typical laniary tooth measures 0*015 in height. 

 The fragmentary plates from the Russian Old Red Sandstone, 

 theoretically associated with the above by Agassiz and Eichwald, 

 are too imperfect for determination. 



Form, fy Log. Upper Old Red Sandstone : Perthshire and Elgin. 



