Figure 15.— Protobalistum imperiale: top. lateral 



views of the two counterparts; middle left, lateral 



view of head, showing pharyngeal and jaw teeth; 



lower right, lateral view of caudal region; 



bottom, lateral view of middle of body (head to right), 



showing remains of scale plates, pectoral fin 



rays, coracoid, and pharyngeal teeth; holotype, 



522 mm SL, Eocene of Monte Bolca, Italy. 



lower jaws, but it cannot be determined if they occurred 

 in a single series or in a major outer series internal to 

 which were a few other teeth. Pharyngeal teeth are pres- 

 ent in the appropriate area at the intersection of the 

 levels of the horizontal through the middle of the mouth 

 and the vertical to the base of the second dorsal fin spine. 

 They are small and more elongate versions of the cusped 

 teeth of the mouth. 



The anterior half of the body exclusive of the head 

 (i.e., in the region below the bases of the second to fifth 

 dorsal spines) is completely (taking into account missing 

 pieces) covered by relatively huge, thick bony plates with 

 numerous rounded bumps or granulations on their sur- 

 face. Many of these plates are distinctly hexagonal, and 

 all of them articulate to one another along all of their 

 edges of apposition by intermeshed delicate denticula- 

 tions, all of this being remarkably similar to the scale 

 plates in ostracioids. Measurements of a few of the more 

 complete scale plates are as follows: a plate below the 

 bases of the fourth and fifth dorsal spines is 56.9 mm 

 (lO.g'^o SL) deep and 64.3 mm (12.3% SL) wide; a plate 

 just below the former is 51.6 mm (9.9% SL) deep and 52.3 

 mm (10.0% SL) wide; one of the few scale plates on the 

 head, approximately midway between the eye and 

 mouth, is about 31 mm (5.9% SL) deep and 27 mm (5.2% 

 SL) wide. While a continuous ostracioidlike carapace ap- 

 parently is present only on the anterior half of the body 

 exclusive of the head, there are numerous, usually much 



