The Ventral Armor of Dinichthys. — Wright. 315 
At the time the monograph was written it was thought by 
Dr. Newberry that he had material representing two addition- 
al pairs of plates which protected the under side of the head. 
These were considered to be the "jugulars" and the "post- 
jugulars" or "hyoids," the latter pair overlapping the former 
pair where the extremities met. In all, therefore, nine bones 
have hitherto been referred to definite positions upon the 
Fig. 2. Ventral armor of Dinichthys terrel/iN., one-twelfth natural size. 
(Dr. Newberry's first restoration.) 
under side of the fish, a jugular series of four and the above 
mentioned ventral series of five. This, I think, was Dr. New- 
berry's latest conception of the arrangement of these plates. 
although he himself made some alterations in his first identi- 
fications of the bones. 
Prior to the publication of the monograph, specimens had 
been obtained which showed that the pair of supposed poste- 
rior ventral plates really belonged upon the sides of the head : 
and in that work they are figured in their true position and 
