i8o 



STUDIES IN THE EVOLUTION OF ANIMALS 



with a circle of plates round the eyes, as shown in Fig. 76, («) 

 and {b), and others in which the eyes were mere holes in a solid 

 one-piece head armour as in (c)?- 



In their descendants, the carapaced land animals, it may have 

 been this circle of plates round the eyes which was early got 



of 



i'lG. 76. — (a) Circle of bone-plates round the eye, Lepidotus maximus, p. 986 ; ib] Tuber- 

 culated bone-plates round the eye of Dapidius phoUdotus, fig. 922 ; [c] Solid bone mask of 

 Cephalaspis Lyelll with an eye-hole at [e], p. 961 (all three Ganoid fishes from Manual af 

 Paleontology, by Nicholson and Lydekker.vol. ii. ) ; {d) is the head of Ostracion functatus, 

 an armour-plated modern fish, with its imarmoured lips at (wz) from pi. 181, Fishes of India, 

 by Francis Day, pt. iv. 



rid of to enable them to close their eyes, if necessary, while moving 

 among bushes, for the protection of their eyeballs. Then there is 

 that curious modern fish called Ostracion, which is encased in hexa- 

 gonal bone-plates all but the lips ; the fins and tail also have no 

 plates round their base. Fig. "^6 (d) gives a sketch of its head. 



1 See Figs. 898. 922, and 926 oi Manual of Palceontology, Nicholson and Lydekker. 



