﻿PLATE III. 



Fig. _ Page 



1. Diphcanthus longispiaus, Ag. ; ventro-lateral aspect of 



fish. — L. Old Red Sandstone; Gamrie. a. Anal fin- 

 spine. cl v d s . Dorsal fin-spines. i. Intermediate pair 

 of spines, pet. Pectoral fin-spines, plv. Pelvic fin- 

 spines, x. Pectoral arch. [P. 4041.] 27 



2. Squaloraja polysponclyla, Ag. ; right mandibular (or left 



palatine) tooth, inner aspect. — L. Lias ; Lyme Regis. 



[43970.] 42 



3. 3 a. Myriacanthus granulatus, Ag. ; left mandibular tooth, 



inner and symphysial aspects.— Ibid. 8. Bevelled sym- 

 physial surface. [P. 3099.] 50 



4. Ditto ; dermal plate, outer aspect, twice nat. size.— Ibid. 



[P. 1158.] 50 



5. Myriacanthus, sp. (?); dorsal fin-spine*— Ibid. 



[P. 2850.] 51 



6. Heteracanthus heterogyrus (Ag.) ; fragment of dermal spine, 



lateral aspect, twice nat. size. — Devonian ; Russia. 



[P. 2248.] 125 



