﻿ICH.THYODORULITES. 137 



P. 3136-7. Two more imperfect examples of the same, one figured 

 loc. cit. pi. lxv. 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 flat, 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 Gyracanthus. 



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, Myriacantlius (p. 43). 

 Similar plates have already been described by E. H'Coy under the 

 names of Coccosteus ? carbonarius \ Asterolepis verrucosa 2 , and Pla- 

 ty acanthus 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.] 



