84 
CHIMiEROIDEI. 
droit,’ and regarded as the type of a Miocene species of 
Ischyodus—Chtmcera ( Ischyodon ) Helvetica ; Molasse, 
Olten, Soleure, Switzerland. The specimen is referred to 
Edaphodon by F. J. Pictet, Paleontologie, ed. 2, vol. ii. 
(1854), p. 233. Egerton Coll. 
The following dorsal fin-spines from the English Chalk may also 
be assigned to Edaphodon :— 
39068. Slender spine, somewhat broken, 0183 in length ; Maid¬ 
stone. Bowerbank Coll. 
36749. Greater portion of similar spine; Hailing, Kent. 
Purchased, 1862. 
43731. Similar spine, wanting extremities ; Lewes. Capron Coll. 
P.1153. Fragments of slender spine ; Kent. Egerton Coll. 
46401. Portion of stouter spine; Lower Chalk, Warminster, Wilt¬ 
shire. Cunnington Coll. 
43390. Portion of large spine; Burham, Kent. Purchased, 1872. 
P. 8255. Fragments of large spine, provisionally assigned by Agassiz 
to Edaphodori [“ Chimcera"^\ mantelli (Poiss. Foss, vol.iii. 
1843, p. 64, pi. x. b. fig. 17) ; Lewes. Mantell Coll. 
P. 3097. Basal portion of similar spine; Lewes. Enniskillen Coll. 
49025-8. Portions of two large spines ; locality uncertain. 
Mrs. Smith's Coll. 
A dorsal fin-spine, probably of Edaphodon, has also been described 
from the Cretaceous of Central Bussia by S. Nikitin, Mem. Comite 
Geol. vol. v. no. 2 (1882), p. 42, pi. iv. fig. 16. Another fin-spine, 
possibly of this genus, from the Cretaceous Greensand of New 
Jersey, is named Sphagepoea acicidata, E. J). Cope, Proc. Amer. 
Phil. Soc. vol. xi. (1869), p. 241, 
The species mentioned below have also been determined upon the 
evidence of detached teeth, and, by a misunderstanding of the 
generic characters, the majority of the American forms have hitherto 
been ascribed to Ischyodus. Most of the type specimens of the 
latter are in the collection of Prof. E. D. Cope, Philadelphia, where 
the present writer has had the privilege of examining them; and 
many of the specific distinctions cited in the diagnoses would be 
regarded as varietal in Britain. Unless otherwise stated, the type 
specimen is a mandibular tooth :— 
