ICHTHYODORULITES. 
109 
39917. Imperfect spine, 0’23 in length ; Denbighshire. 
Purchased , 1866. 
The following specimen may also be referred to Acondylacan- 
thus :— 
49652. Portion of an extremely compressed slender spine, with 
fine, smooth, superficial longitudinal ridges ; Upper 
Carboniferous Limestone, Richmond, Yorkshire. 
^- /r ft*? e Ate 5 « Purchased , 1878. 
The following species have also been ascribed to this genus:— 
Acondylacanthus cequicostatus , St. John & Worthen, Pal. Illinois, 
vol. vi. (1875), p. 434, pi. xvi. figs. 12, lg/— Keokuk 
Limestone; Illinois. 
Acondylacanthus gracilis , St. John & Worthen, op. cit. yoI. vi. 
p. 433, pi. xvi. figs. 8-11.—Kinderhook Limestone ; Iowa. 
[The type species.] 
Acondylacanthus jenkinsoni, St. John & Worthen, op. cit. vol. vi. 
p. 433; J. W. Davis, Trans. Roy. Dublin Soc. [2] vol. i. 
p. 351, pi. xlvi. fig. 2 : Leptacanthus jenkinsoni, P. M‘Coy, 
Brit. Palaeoz. Ross. 1855, p. 633, pi. iii. o. figs. 14-16.— 
Carboniferous Limestone ; Lowick, Northumberland. 
[Woodwnrdian Museum, Cambridge.] 
Acondylacanthus junceus , St. John & Worthen, op. cit. vol. vi. 
p. 433; J. W. Davis, Trans. Roy. Dublin Soc. [2] vol. i. 
p. 350, pi. xlvi. fig. 6 : Leptcccanthus junceus , P. M‘Coy, 
Ann. Mag. Nat. Hist. [2] vol. ii. (1848), p. 122, and Brit. 
Palaeoz. Poss. (1855), p. 633, pi. iii. &. fig. 13.—-Carbon¬ 
iferous Limestone; Derbyshire. [Woodwardian Museum,] 
Acondylacanthus occidentals, St. John & Worthen, op. cit. vol. vi. 
p. 433; J. S. Newberry, Palaeoz. Pishes N. America (Mon. 
U.S. Greol. Surv. no. xvi. 1889), p. 206, pi. xxv. fig. 6 : 
Leptacanthus ? occidentals, Newberry & Worthen, Pal. 
Illinois, vol. ii. (1866), p. 116, pi. xii. fig. 2 : Ctenacantlms 
gracillimus, Newberry & Worthen, ibid. p. 126, pi. xiii. 
fig. 3; St. John & Worthen, op. cit. vol. vii. (1883), p. 238, 
pi. xxiv. fig. 1.—St. Louis Limestone; Missouri, Illinois, 
and Michigan. ^ 
Acondylacanthus rectus , St. John <k Worthen, op. cit. vol. vii. p. 241, 
pi. xxvi. fig. 2.—Upper Coal-Measures ; Illinois. 
Acondylacanthus remotus: Leptacanthus remotus, E. von Eichwald, 
Leth. Rossica, vol. i. (1860), p. 1601, pi. lvi. fig. 4.— 
Carboniferous Limestone; Ralouga, on River Protva, 
Russia. [University of St. Petersburg.] 
