CESIEACIONTID^. 
305 
(b) Cephalic Sjtines. 
2691. T}'pe specimen of Sphenonehus elongatus, Agassiz, tom. cit. 
p. 202, pi. xxii.a. fig. 18 ; Tilgate Forest. Mantell Coll. 
P. 4919. One small spine, the basal portion of another, and the 
exserted portion of one larger spine ; Hastings. 
Dawson Coll. 
VIII. Cretaceous. (a) Dorsal Fin-spitws. 
47228. Portion of a small spine, with few widely-spaced sharp ribs ; 
Gault, Folkestone. Gardner Coll. 
30260, 35168, 35352-3, 35461. Nine more or less abraded frag- 
ments of spines ; Cambridge Greensand, Cambridge. 
Purchased. 
P. 2173. Two similar fragments ; Cambridge. Egerton Coll. 
P. 4328. Another fragment ; Cambridge. Enniskillen Coll. 
P. 2830. Large abraded and crushed spine, described under the 
name of Hyhodws complaiuitus, 11. Owen, Geol. Hag. vol. vi. 
(1869), p. 482 ; Upper Greensand, Maidstone, Kent. 
Enniskillen Coll. 
(b) Cephalic Spine. 
P. 2296. Portion of a spine equalling those of the Liassic Hybo- 
donts in size ; Grey Chalk, Dover, Kent. 
Presented by Mrs. Burton, 1882. 
The following dorsal fin-spines resembling those of Hyhodus and 
Acrodus have also been named: — 
Hyhodus acanthophoi-us, T. C. Winkler, Archiv, Mus. Teyler, vol. v. 
livr. 2 (1880), p. 122, pi. vi. figs. 19-21, pi. iii. figs. 22- 
26. — Keuper ; Wurzburg. 
Hyhodus angulatus, G. von Munster, Beitr. Petrefakt. iv, (1841), 
p. 141, pi. xvi. fig. 17.— Trias ; S.E. Tyrol. 
Hyhodus dewalquei, H. Forir, Ann. Soc. Geol. Belg. vol. xiv. 
(1887), p. 29, pi. ii. fig. 1. — Upper Cretaceous ; Belgium. 
Hyhodus ekhwaldi, V. Kiprijanoff, BuU. Soc. Imp. Nat. Moscou, 
1853, pt. i. p. 331, pi. vi. ; ihid. 1855, pt. i. p. 392, pi. ii. 
— Cenomanian ; Government of Kursk, Kussia. 
Hyhodus ensatus, L. Agassiz, Poiss. Foss. vol. iii. (1837), p. 51, 
pi. ix. fig. 12. — Lower Lias ; Lyme EegLs. 
X 
