200 B. NATURAL HISTORY. 
etal. (See figs. 2,3,Sq.) Though it cannot yet be asserted that 
this is one primary element, yet in the adult Ichthyosaurus there is 
ft V4 WY 
\ 
TAA NAA, 
TY 
J] 
} 
Cranium of Ichthyosaurus without arches. 
Col, Columella. Pt, Pterygoid. 
(The anterior extremity of the sphenoid is imperfect.) 
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