﻿L06 1CHTHY0D0RULITES. 



L888. Homacanthus microdus, J.W. Davis, Trans. Roy. Dublin Soc. [2] 

 vol. i. p. 361, pi. xlviii. tigs. 7-9. 



Type. Woodwardian Museum, Cambridge. 



Form. Sf hoc. Lower Carboniferous Limestone ; Armagh, Ireland. 



P. 2516-18. Three spines, described and figured by J. W. Davis, 

 loc. cit. EnnisTcillen Coll. 



P. 2515. Ten specimens, the majority very imperfect. 



Enniskillen Coll. 



The following specimens are somewhat smaller than H. mzcrodus, 

 with more numerous longitudinal ridges than the foregoing : — , 



42258. Spine, imperfect distally und proximally; Carboniferous 

 Limestone, Shropshire. Baugh Coll. 



P. 2247. Distal portion of spine, gently arched, with traces of 

 well-developed posterior denticles, labelled Onchus subulatus 

 in Agassiz's handwriting, and doubtless intended to be the 

 type specimen of that species (named in Poiss. Foss. 

 vol. iii. 1843, p. 177) ; Coal-Measures, Ruabon, Denbigh- 

 shire. Egerton Coll. 



The following species has also been described : — 



Homacanthus macrodus, F. M'Coy, Ann. Mag. Nat. Hist. [2] 

 vol. ii. (1848), p. 115, and Brit. Palseoz. Foss. (1855), 

 p. 632, pi. iii.K. fig. 20 ; J. W. Davis, Trans. Roy. Dublin 

 Soc. [2] vol. i. (1883), p. 362.— Lower Carboniferous 

 Limestone; Armagh. [Woodwardian Museum, Cambridge.] 



Two spines from the St. Louis Limestone of Missouri and Illinois 

 have also been described under the names of Homacanthus gibbosus, 

 Newberry & Worthen (Pal. Illinois, vol. ii. 1866, p. 113, pi. xii. 

 fig. 1), and H. ? rectus, Newberry & Worthen {ibid. p. 115, pi. xii. 

 fig. 6). The former is now made the type of the genus Amacanthus, 

 St. John & Worthen (Pal. Illinois, vol. vi. 1875, p. 464, pi. xxii. 

 fig. 6), and the latter that of Marracanihus, St. John & Worthen 

 (ibid. pp. 465, 466, pi. xxii. figs. 7-9). . 



The spine named Homacanthus gracilis, J. F. Whiteaves (Trans. 

 Roy. Soc. Canada, vol. vi. sect. iv. 1*888, p. 96, pi. x. fig. 4), is also 

 doubtfully determined, and may belong to an Acanthodian fish 

 resembling Climatius. The type specimen was obtained from the 

 Lower Devonian of Campbellton, New Brunswick, and is preserved 

 in the Geological Survey Museum, Ottawa. 



