ICHTHYODORTJLITES. 
115 
P. 2233. Spine and fragment, the former exhibiting the lateral 
ornament and anterior keel; Lower Coal-Measures, Low- 
moor, Yorkshire. The spine is shown, of natural size, in 
Pig. 9. 
Lepracanthus colei, Owen. Coal-Measures, Kuabon. [P.2861.] 
Plate I. fig. 1, and a portion of the ornament is enlarged 
four times in fig. 1 a. Egerton Coll. 
P. 2902. More arched spine ; Lowmoor. Enniskillen Coll. 
Genus NEMACANTHUS, Agassiz. 
[Poiss. Poss. vol. iii. 1837, p. 25.] 
Syn. I)es?nacant7ius, F. A. Quenstedt, Der Jura, 1858, p. 34. 
Dorsal fin-spines of small or moderate size, much laterally com¬ 
pressed, nearly straight; sides of exserted portion marked with fine 
longitudinal striae, thus not sharply separated from the inserted 
portion, though exhibiting large, rounded, ganoine-coated tubercles, 
in longitudinal series, covering a variable extent ; anterior margin 
prominently keeled ; posterior face with a row of small pointed 
denticles upon each edge. 
12 . 
