﻿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. 



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, 13.— Keokuk 

 Limestone ; Illinois. 



Acondylacanthus gracilis, St. John & Worthen, op. cit. vol. 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. Eoy. Dublin Soc. [2] vol. i. 

 p. 351, pi. xlvi. fig. 2 : Leptacanthus jenJcinsoni, F. M'Coy, 

 Brit. Palaeoz. Foss. 1855, p. 633, pi. iii. o. figs. 14-16.— 

 Carboniferous Limestone ; Lowick, Northumberland. 

 [Woodwardian Museum, Cambridge.] 



Acondylacanthus junceus, St. John & Worthen, op. cit. vol. vi. 

 p. 433 ; J. W. Davis, Trans. Eoy. Dublin Soc. [2] vol. i. 

 p. 350, pi. xlvi. fig. 6 : Leptacanthus junceus, F. M'Coy, 

 Ann. Mag. Nat. Hist. [2] vol. ii. (1848), p. 122, and Erit. 

 Palaeoz. Poss. (1855), p. 633, pi. iii. g. fig. 13. — Carbon- 

 iferous Limestone ; Derbyshire. [Woodwardian Museum.] 



Acondylacanthus occidentalis, St. John & Worthen, op. cit. vol. vi. 

 p. 433 ; J. S. Newberry, Palasoz. Pishes N. America (Mon. 

 U.S. Geol. Surv. no. xvi. 1889), p. 206, pi. xxv. fig. 6 : 

 Leptacanthus ? occidentalis, Newberry & Worthen, Pal. 

 Illinois, vol. ii. (1866), p. 116, pi. xii. fig. 2 : Ctenacanthus 

 f/racillimus, 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 & Worthen, op. cit. vol. vii. p. 241, 

 pi. xxvi. fig. 2. — Upper Coal-Measures ; Illinois. 



Acondylacanthus remotus : Leptacanthus remotus, E. von Eichwald, 

 Leth. Eossica, vol. i. (1860), p. 1601, pi. lvi. fig. 4.— 

 Carboniferous Limestone; Kalouga, on Eiver Protva, 

 Eussia. [University of St. Petersburg.] 



