WELLBURN : FISH FAUNA OF YORKSHIRE COAL MEASURES. 165 
Sp. A. major Davis, 1894. 
To the author it appears to be certain that there are two 
species of Acanthodes in the Yorkshire Coal Measures, one being 
a very much larger species than A. Wardi. I have seen spines 
of this species fully seven inches in length, and after having 
examined some hundreds of these spines of Acanthodes, I have 
not been able to trace any intermediate forms which would 
suggest that A. Wardi was a young form of the larger species, 
and this being so it — to me — seems justifiable for the present to 
retain A. major Davis for the larger forms. 
Fairly common, but distribution limited. 
Genus : Acanthodopsis Handcock and Atthey, 1868. 
Sp. A. Wardi Handcock and Atthey, 1868. 
Part of a jaw with teeth. 
Rare, distribution very limited. 
ICHTHYODORULITES. 
Genus : Homacanthus Agassiz, 1845. 
Sp. H. microdus McCoy, 1848. 
Two spines in the author's collection show well the characters 
of this species. 
Form, and Loc. : Shale above the Crow Coal, Leeds, and 
Better Bed Coal, Low Moor. 
Genus : Hoplonchus, 1876. 
Sp. H. elegans Davis, 1876. 
There are two distinct forms of the spines of this species, one 
being straighter, longer, and more robust than the other, which 
is much more arched and slender. They are probably the anterior 
and posterior dorsal fin spines of the fish. To the author this 
genus appears to be distinct from the last. 
Not common, distribution limited. 
Genus : Ostracanthus Davis, 1879. 
Sp. 0. dilatus Davis, 1879. 
Only the type specimen is known, and to the author it 
appears to be probable that the Ichthyolite may be the basal 
portion of a spine of some species of Pleur acanthus. 
Form, and Loc. : Cannel Coal, Tingley. 
