242 
SELACHII. 
suggestion made, with hesitation, by Dr. Traquair, and adopt the 
provisional name of Sphenacanthus for the fish. 
Sphenacanthus serrulatus, Agassiz. 
1837. Sphenacanthus serrulatus, L. Agassiz, Poiss. Fos3. vol. iii. p. 24, 
pi. i. figs. 11-13. 
1884. Ctenacanthus (P) serrulatus, B. H. Traquair, Geol. Mag. [3] vol. i. 
p. 6. 
Type. Imperfect dorsal fin-spine ; Edinburgh Museum. 
The type species known only by the dorsal fin-spine, which attains 
a maximum length of about 0*15, and is ornamented by sharp 
ridges, in part sparsely nodose. 
Form. Loo. Calciferous Sandstones : Burdiehouse, near Edin¬ 
burgh. 
15506 a. Very imperfect spine ; Burdiehouse. Purchased. 
Sphenacanthus costellatus (Traquair). 
1884. Ctenacanthus costellatus, B. H. Traquair, Geol. Mag. [3] vol. i. 
p. 3, pi. ii. 
(P) 1888. Ctenacanthus costellatus (?), B. H. Traquair, loc. cit. vol. v. 
p. 81. 
Type. ISTearly complete fish ; British Museum. 
Crown of tooth with slender cusps almost or quite smooth. Bibs 
of the dorsal fin-spines ornamented with numerous finely-grooved 
tubercles. 
Form. Loc. Calciferous Sandstones : Dumfriesshire. 
P. 5900. Type specimen, parti) 7 preserved in counterpart, described 
by B. H. Traquair, loc. cit., 1884. Purchased , 1883. 
Sphenacanthus hybodoides (Egerton). 
1853. Ctenacanthus hybodoides, Sir P. Egerton, Quart. Journ. Geol. 
Soc. vol. ix. p. 280, pi. xii. 
1853. Ctenacanthus nodosus, Sir P. Egerton, ibid. p. 281. 
1869. Ctenacanthus major , J. Thomson, Brit. Assoc. Bep., Trans. Sect. 
p. 102. 
1871. Ctenacanthus hybodoides , J. Thomson, Trans. Geol. Soc. Glasgow, 
vol. iv. pt. i. p. 59, pis. ii., iii. 
1873. Ctenacanthus (? and Cladodus), T. P. Barkas, Coal-Meas. Palseont. 
p. 21, figs. 43-58 (?p. 19, figs. 31-34). 
1874. Hybodus, W. J. Barkas, Geol. Mag. [2] vol. i. p. 163. 
