ICHTH rODORULITES. 
113 
Cosmacanthus stellatus : Geisacantlius stellatus, St. John & 
orthen, tom. cit. p. 440, pi. xxi. fig. 10. — Upper 
St. Louis Limestone; Missouri. [The type species of 
Geisacantlius. ] 
Four other Lower Carboniferous genera of tuberculated spines, 
with a deep base of insertion, and {wobably for the most part 
bilaterally symmetrical, are also recognized, as follows:— 
Bythiacanthus, 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 Asteracanthus siderius , J. Leidy, Proc. Acad. Hat. Sci. 
Philad. 1870, p. 13, and Ext. Vert. Fauna W. Territ. (Pep. 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 Omccm^ws-shaped 
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. ruclis , St. John 
& Worthen (op. cit. vol. vii. p. 249, pi. xxv. fig. 1), from the Keokuk 
Limestone of Iowa. 
Thciumatacanthus , W. Waagen, Salt-Pange Fossils (Pakeont. 
Indica, ser. 13), vol. i. (1880), p. 78, with the single species, 
T. blanforcli, Waagen (ibid. p. 79, pi. viii. fig. 1), from the Upper 
Productus Limestone of Kiri, in the Salt Range, Punjab, India. 
[Indian Museum, Calcutta.] 
Chalazacanthus , J. W. Davis, Trans. Koy. 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. Koy. 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 
