106 
ICHTHYODOKULITES. 
1883. Homacanthus microdus, J. W. Davis, Trans. Roy. Dublin Soc. [2] 
vol. i. p. 361, pi. xlviii. figs. 7-9. 
Type. Woodwardian Museum, Cambridge. 
Form. Sf Log. Lower Carboniferous Limestone ; Armagh, Ireland. 
P. 2516-18. Three spines, described and figured by J. W. Davis, 
loc. cit. Enniskillen Coll. 
P. 2515. Ten specimens, the majority very imperfect. 
Enniskillen Coll. 
The following specimens are somewhat smaller than H. microdus , 
with more numerous longitudinal ridges than the foregoing :— 
42258- Spine, imperfect distally and proximally; Carboniferous 
Limestone, Shropshire. Baugh Coll. 
P. 2247. Distal portion of spine, gently arched, with traces of 
well-developed posterior denticles, labelled Onchus subulcitus 
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, Buabon, 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. Boy. 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 Amacanihus, 
St. John & Worthen (Pal. Illinois, vol. vi. 1875, p. 464, pi. xxii. 
fig. 6), and the latter that of Merer a can thus , St. John & Worthen 
(ibid. pp. 465, 466, pi. xxii. figs. 7-9). 
The spine named Homacanthus gracilis, J. F. Whiteaves (Trans. 
Boy. Soc. Canada, vol. vi. sect. iv. 1888, 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. 
