52 



FISH GALLERY. 



Pteraspis. 



(Lampreys and Hag-fishes). They were probably bottom-feeders 

 and of sluggish habits. The models exhibited were constructed 

 mainly from descriptions and figures in " The Fishes of the Old 

 Red Sandstone/' (Palseont. Soc), by E. Ray Lankester, 1868, 



Fig. 28. — Restoration of Pteraspis rostrata, side view. 

 (After A. S. Woodward.) 



and R. H. Traquair, 1894, 190.2, 1904, and from the Geol. Mag., 

 1902 (Traquair), and from specimens in the Geological Department 

 of the Museum. 



The first two specimens (160 and 161) show the upper and under 

 surfaces of Pteraspis rostrata ; the models are 2^- times natural 



Fig. 29. — Dorsal shield of Pteraspis rostrata, upper view. 

 (After Lanliester.) 



size (linear enlargement). The hinder part of the tail is not 

 shown, since nothing is known of its shape or length. 



In Pteraspis (see figs. 28 and 29) the chief body plates are a 

 conical plate in front, a large dorsal plate with a spine projecting 

 from its hinder edge, a pair of long side plates, and a large ventral 

 plate. The ventral plate was at first thought to belong to a 

 different animal, and was named " Scaphaspis." The eye is 

 small and lateral, and the exhalent aperture of the gill-chamber is 



