ICHTHYODORTJLITES. 
137 
P. 3136-7. Two more imperfect examples of the same, one figured 
loc. cit. pi. Ixy. fig. 4 ; Armagh. Enniskillen Coll. 
P. 2887. Smaller portion probably of a similar plate, figured loc. 
cit. pi. lxii. fig. 13 ; Armagh. Enniskillen Coll. 
The following spines may also pertain to this species, but differ 
from the foregoing in their slenderness, and in the fusion of the 
superficial tubercles into oblique transverse ridges: — 
P. 2238. Fragment of a small spine, narrow and straight; Armagh. 
Egerton Coll. 
P. 3134, P. 3134 a. Larger portion of a similar spine, free from 
matrix ; also a fragment; Armagh. The spine (PI. I. 
fig. 3) is much compressed, with the convex edge acute, 
and worn at the distal end; the opposite edge being 
straight and fiat, or longitudinally channelled. So far as 
preserved, the specimen seems to be bilaterally symme¬ 
trical ; and the oblique lateral ridges are inclined in an 
exactly opposite direction to those of Gyrcicanthus. 
Enniskillen Coll. 
P. 3127. Remains of a larger more arched spine ; Castle Espie, Co. 
Down, Ireland. Enniskillen Coll. 
The numerous small dermal plates mentioned below are also 
provisionally associated with Oracanthus milleri by J. W. Davis, loc. 
cit. They are thin, consist of vascular dentine, and are externally 
ornamented with rounded ganoine-tubercles, irregularly disposed. 
Their nearest known analogues are perhaps to be found in the 
dermal plates of the Liassic Chimaeroid, Myriacanthus (p. 43). 
Similar plates have already been described by E. IPCoy under the 
names of Coccosteus ? carbonarius 1 , Asterolepis verrucosa 2 , and Pla- 
tydeanthus isosceles 3 ; and the triangular forms are named Pnigea- 
canthus by St. John & Worthen, loc. cit. 
All these specimens were obtained from the Lower Carboniferous 
Limestone of Armagh, and are from the Enniskillen Collection. 
P. 2876-7. Elongated symmetrical plate, bifurcated at one ex¬ 
tremity, and portion of a similar plate, figured, loc. cit. 
pi. lxii. figs. 1, 2 (“ central dorsal bone of cranium ”). 
1 Ann. Mag. Nat. Hist. [2] vol. ii. (1848), p. 9. [Geol. Soc. London.] 
2 Ibid. p. 9. [Geol. Soc. London.] 
3 Ibid. p. 120. [Geol. Soc. London.] 
