﻿[CH TH YODORULIT ES . 113 



Cosmacanihus atellatus : Geisacantlms stellatus, St. John & 

 Worthen, torn. cit. p. 440, pi. xxi. fig. 10. — Upper 

 St. Louis Limestone; Missouri. [The type species of 

 Geisacanihus.~\ 



Four other Lower Carboniferous genera of tuberculated spines, 

 with a deep base of insertion, and probably for the most part 

 bilaterally symmetrical, are also recognized, as follows : — 



BythiacantJius, St. John & Worthen (Pal. Illinois, vol. vi. 1875, 

 p. 444), comprising B. van-hornei, St. John & Worthen (ibid. p. 445, 

 pi. xvii. fig. 1), from the Upper St. Louis Limestone of Illinois ; and 

 the so-called Asteracanihus siderius, J. Leidy, Proc. Acad. Nat. Sci. 

 Philad. 1870, p. 13, and Ext. Vert. Fauna W. Territ. (Rep. U.S. 

 Geol. Surv. Territ. vol. i. 1873), p. 313, pi. xxxii. fig. 59, probably 

 from the St. Louis Limestone of Tennessee. [The second fossil, now 

 in the Museum of the Academy of Sciences, Philadelphia, may 

 be a broken piece of the abraded border of an Oracanthus-shsi^ed 

 spine.] 



Glymmatacanthus, St. John & Worthen (op. cit. vol. vi. p. 446), 

 comprising G. irishi, St. John & Worthen (ibid. p. 447, pi. xvii. 

 fig. 2), from the Upper Kinderhook Limestone of Iowa; G. petro- 

 doides, St. John & Worthen (op. cit. vol. vii. 1883, p. 250, pi. xxv. 

 fig. 2), from the Chester Limestone of Illinois ; and G. rudis, St. John 

 & AVorthen (op. cit. vol. vii. p. 249, pi. xxv. fig. 1), from the Keokuk 

 Limestone of Iowa. 



Thaumatacanthus, W. Waagen, Salt-Eange Fossils (Pala3ont. 

 Indica, ser. 13), vol. i. (1880), p. 78, with the single species, 

 T. blanfordi, Waagen (ibid. p. 79, pi. viii. fig. 1), from the Upper 

 Productus Limestone of Kiri, in the Salt Eange, Punjab, India. 

 [Indian Museum, Calcutta.] 



CJialazacantJms, J. W. Davis, Trans. Roy. Dublin Soc. [2] vol. i. 

 (1883), p. 370, with the single species C. verrucosus, Davis (ibid. 

 p. 371, pi. xlviii. fig. 13), from the Lower Carboniferous Limestone 

 of Bristol. [Bristol Museum.] 



Genus LISPACANTHUS, Davis. 



[Trans. Roy. Dublin Soc. [2] vol. i. 1883, p. 359.] 



Dorsal fin-spine of medium size, slender, laterally compressed, and 

 gradually tapering ; sides of exserted portion apparently smooth ; 

 posterior face with a median longitudinal keel, but no denticles ; 

 base-line of exserted portion very oblique. 



PART II. I 



