14 PROCEEDINGS OF THE NATIONAL MrjSEUM. vol. o.U 



Plate 1. 



Dorsal view of skull of Parietobalaena palmeri. About one-third natural size. 

 Abbreviations : C. condyle ; Ex. o. exoccipital ; Fr. frontal ; Max. s. maxil- 

 lary sutures ; Na. s. nasal sutures ; Pa. parietal ; Pmx. s. premaxillary 

 sutures ; Po. p. postorbital projection of frontal ; Pr. p. preorbital projection 

 of frontal ; So. supraoccipital ; Sq. squamosal. 



Plate 2. 



Posterior view of skull of Parietohal<iena palmeri. About seven-sixteenths 

 natural size. Abbreviations : Bo. basioccipital ; C. condyle ; Ex, o. exocci- 

 pital ; Fo. m. foramen magnum ; Meat. aud. ext. meatus auditorius ex- 

 ternus ; Pa. parietal ; Po. gl. p. postglenoid process ; Po. p. postorbital projec- 

 tion of frontal ; So. supraoccipital ; Sq. squamosal. 



Plate 3. 



Lateral view of skull of ParietobaJaena palmeri. About one-half natural size. 

 Abbreviations : Ex. o. exoccipital ; Ex. pt. external pterygoid ; Fo. ov. 

 foramen ovale ; Fr. frontal ; Meat. aud. ext. meatus auditorius externus ; Pa. 

 parietal ; Po. gl. p. postglenoid process ; Po. p. postorbital projection ; Pr. p. 

 preorbital projection ; Sph. f. sphenoidal fissure ; Sq. squamosal. 



Plate 4. 



Ventral view of skull of Parietoialaena palmeri. About one-third natural size. 

 Abbreviations : Ap. per. apophysis of periotic ; Bo. basioccipital ; Bs. basi- 

 sphenoid ; C. condyle ; Can opt. canalis opticus ; Ex. o. exoccipital ; Ex. pt. 

 external pterygoid ; Fo. opt. foramen opticus ; Fo. ov. foramen ovale ; Fr. 

 frontal ; Fo. lac. post, foramen lacerum posterius ; Ol. f. glenoid fossa ; In. 

 pt. internal pterygoid ; Meat. and. ext. meatus auditorius externus ; Per. 

 periotic ; Po. gl. p. postglenoid process of squamosal ; Po. p. postorbital 

 projection of frontal ; Pi: falc. processus falciformis ; Pr. p. preorbital pro- 

 jection of frontal ; Prs. presphenoid ; S. or. pr. supraorbital process of 

 frontal ; Sq. squamosal ; Zyg. zygomatic process of squamosal. 



Plate 5. 



Right periotic of Parietobalaena palmeri. Fig. 1, Superior view about five- 

 eighths natural size; Fig. 2, Superior view, posterior apophysis removed, 

 about three-fourths natural size: Fig. 3, Inferior view, about flve-eighths 

 natural size ; Fig. 4, Inferior view, posterior apophysis removed, malleus in 

 place, about three-fourths natural size. Abbreviations: A. M. internal 

 acoustic meatus : A. ped. anterior pedicle ; Aq. c. aquaeductus cochleae ; Aq. 

 V. aquaeductus vestibuli : F. C. facial canal ; F. ov. fenestra ovalis ; F. and 

 F. r. fenestra rotundum; Inctis (this is not the incus as stated in text and 

 should be labeled malleus) ; Pr. a. pt. processus anterior petrosi ; Pr. po. 

 pt. processus posterior petrosi. 



Plate 6. 



Left tympanic of Parietobalaena palmeri. Fig. la, Superior view ; Fig. 1&, 

 External view. 



Tympanic bones of undetermined fossil cetacean, Cat. No. 10, 722, United 

 States National Museum. Fig. 2a, Left tympanic. Inferior view; Fig, 2b, 

 Left tympanic. External view ; Fig. 3a, Right tympanic, Superior view ; 

 Fig. 3&, Right tympanic. External view. Figures about five-sevenths nat- 

 ural size. 



