PYGOPTERUS GREKNOCKII. 713 



Fig. 3. Upper surface of the cranial buckler of the same specimen represented in fig. 2 

 natural size. 

 N, N, Nasal openings. 



7, 7, Parietal bones; 8, 8, Mastoids ; 11, 11, Frontals ; 12, 12, Post-frontals ; 

 14, 14, Pre-frontals; 15, Nasal. 

 Fig. 4. Front view of snout of same specimen. 

 N, N, Nasal openings. 

 14, 14, Pre-frontals; 15, Nasal; 22, 22, Pre-maxillaries. 



Fig. 5. Scales of Pygopterus Greenockii. 



A, Scale from the anterior part of the flank of the fish magnified two diameters, 

 showing concentric lines of growth, the external layer of ganoine having scaled 

 off. 



B, Outline of a scale from the hinder part of the flank. 



C, Scale from anterior part of the flank, magnified three diameters, and showing 

 part of the external striated layer of ganoine. 



Fig. 6. Exposed surfaces of scales from posterior part of flank, magnified two diameters. On 

 one of those the external striation is represented. 



Fig. 7- Portion of edge of lower jaw, showing two sizes of teeth. 



Fig. 8. Diagram of side of head of Eurynotus. The numbers apply to the same bones as 

 in fig. 2. 



Fig. 9. Diagram of arrangement of branchiostegal rays in Eurynotus. 



Fig. 10. Diagram of side of head in Amblypterus. 



Fig. 11. Diagram of head of Amblypterus, seen obliquely from the side, and from below. 



Fig. 12. Superior maxillary bone of Eurynotus, seen from the inside; natural size. From 



South Queensferry. 

 Fig. 13. Palate (1) bone of Eurynotus, with crushing teeth. From the same locality. 



VOL. XXIV. PAKT III. .9 H 



