PLATE XXI. 



(The cost of this plate has been defrayed by the Carnegie Trust for the Universities 



of Scotland.) 



Fig. 



1. Gonatodus parvidcns, Traquair ; from a specimen from Wallyford, Midlothian. In 



the British Museum. Natural size. 



2. Another specimen, wanting the head and shoulder, probably referable to the same 



species. From the Lower Possil Ironstone, Possil, Lanarkshire ; natural size. 

 James Thomson Collection in the Kilmarnock Museum. 



3. Flank scale from a specimen from the Borough Lee Ironstone, Loanhead ; magnified 



three diameters. Collection of the Author. 



4. Maxillary bone with teeth seen from the inner aspect ; magnified two diameters. 



From the Borough Lee Ironstone. In the Collection of the Author. 



5. Dentary bone of mandible with teeth, seen from the inside, and magnified two and 



a half times. From the Borough Lee Ironstone. In the Collection of the Author. 

 (5. Wax impression of the commencement of the dorsal fin in the specimen represented 



in fig. 1 ; magnified. 

 7. Wax impression of the anterior margin of the ventral fin in the same specimen ; 



magnified. 



