﻿ICHTHYODOTtTTLTTES. 1 23 



III. Paired spines of which some may have been placed in front of 

 fins, but of which many are broad, with insignificant base of 

 insertion, and must have been arranged as independent dermal 

 armour. 



Genus MACH5IRAC ANTHUS, Newberry. 



[Bull. National Institute, 1857, p. 6.] 



Syn. Machcerius, M t Renault, Comptes Rendus, vol. xlvii. 1858, p. 102 

 (preoccupied). 



Spines, so far as known, elongated, tapering, more or less curved, 

 and somewhat laterally compressed, with sharp edges and a large 

 longitudinal ridge on each side ; central cavity extending nearly to 

 the apex ; external surface covered with a thin layer of gano- 

 dentine, smooth, finely punctate, or longitudinally striated. 



Machseracanthus sulcatus, Newberry. 



1843. "Ichtkyodorulite," J. Hall, Nat. Hist. New York, pt. iv. p. 174, 



woodc. fig. 69. 

 1857. Machcer acanthus sulcatus, J. S. Newberry, Bull. Nat. Inst. p. 6. 

 1870. Machairacanthus sulcatus, E. R. Lankester, Geol. Mag. vol. vii. 



p. 398, woodc. fig. 3. 

 1873. Machceracantlius sulcatus, J. S. Newberry, Rep. Geol. Surv. Ohio, 



vol. i. pt. ii. p. 305. 

 1886. Machceracantlius sulcatus, T. H. Lennox, Proc. Canad. Inst. 



vol. iii. p. 120. 

 1889. Machcer acanthus sulcatus, J. S. Newberry, Paheoz. Fishes N. 



America (Mon. U.S. Geol. Surv. no. xvi.), p. 40, pi. xxix. fig. 5. 



Type. Delaware University, Ohio. 



lorm. Sf Loc. Lower Devonian (Corniferous Limestone) : Ohio, 

 New York, Ontario, and Canada. 



P. 6216. Impression of part of spine, apparently the specimen 

 figured by Lankester, loc. cit. ; Gaspe, Canada. 



Presented by Sir J. William Dawson, K.C.M.G., 1890. 



The following species are also recognized, but there are no 

 examples in the Collection : — 



Maclicer 'acanthus abnormis : Ctenacanthus abnormis, C. G. Giebel 

 Abh. Naturw. Yereins Provinz Sachsen u. Thiiringen, vol. i. 

 (1858), p. 264, pi. i. fig. 12 ; J. Barrande, Syst. Silur. 

 Boheme, Suppl. to vol. i. (1872), p. 628 : E. Kayser, Abh. 

 geol. Specialk. Preuss. u. Thiiring. Staaten, vol. ii. pt. iv. 



