148 
ICHTHYODOKULITES. 
of Erismacanthus , but cannot be certainly determined. The spine 
is laterally compressed, gently arched, tapering, and ornamented 
with fine superficial tubercles. 
The imperfect Ichthyodorulites from the Lower Carboniferous of 
the United States, described under the names of Gampsciccinthus , 
St. John & Worthen (Pal. Illinois, yoI. vi. 1875, p. 471), and Lecra- 
ccintlius , St. John & Wort-hen (ibicl. p. 475), appear to be fragments 
of Erismacanthus-sh.eL])ed spines. To the former “ genus ” are as¬ 
signed G. ? latus, St. John & Worthen (ibid. p. 474, pi. xxii. fig. 14)', 
from the Keokuk Limestone of Missouri; G. squcimosus, St. John & 
Worthen (ibid. p. 473, pi. xxii. fig. 13), from the Upper St. Louis 
Limestone of Missouri; and G. typus, St. John & Worthen (ibid. 
p. 472, pi. xxii. fig. 12), from the Upper St. Louis Limestone of 
Illinois and Missouri. Lecracanthus has only a single species, L. 
unguiculus , St. John & Worthen (ibid. p. 476, pi. xxii. figs. 10,11), 
from the Upper St. Louis Limestone of Missouri and Illinois. 
A fragment, probably of a similar nature, from the Lower Car¬ 
boniferous Limestone of Armagh, forms the type of Dipriacanthus, 
F. M‘Coy (Ann. Mag. Nat. Hist. [2] vol. ii. 1848, p. 121), with 
the single species, D. stoJcesii , F. M‘Coy (ibid. p. 121, and Brit. 
Palaeoz. Foss. p. 627, pk iii. s. fig. 18), noticed later by J. W. Davis, 
Trans. Boy. Dublin Soc. [2] vol. i. (1883), p. 360, pi. xlviii. fig. 10. 
[Woodwardian Museum, Cambridge.] 
Genus LiISTRAGABJTH!US ? Kewberrv & Worthen. 
[Pal. Illinois, vol. iv. 1870, p. 371.] 
SypH pyt , small, gently arched, and much laterally compressed, ex- 
/^AA^ty^^panding and abruptly truncated at the base. Sides ornamented 
S jth l^imerous acute longitudinal ridges ; the concave and convex 
margins provided with many divergent, slender denticles, pointing 
towards the apex of the spine. 
The type species is L. hystrix, Newberry & Worthen (tom. cit. 
p. 372, pi. ii. fig. 3), from the Coal-Measures of Illinois and Ohio 1 . 
Spines from the Upper Carboniferous Limestone Series of Mons, 
Belgium, are also assigned to this species by L. G. de Koninck 
(Faune Calc. Carbf. Belg. pt. i. 1878, p. 75, pi. v. fig. 11), and the 
following specimen resembles the latter :— 
47307. Spine 0-015 in length, but wanting the apex ; Castiaux, 
near Mons, Belgium. In this specimen the alternate 
1 J. S. Newberry,. Bep. G-eol. Snrv. Ohio, vol. i. pt. ii. (1873), p. 337, and 
ibid. vol. ii. pt. ii. (1875), p. 56, pi. lix. fig. 5. 
