18 PROCEEDINGS OF THE NATIONAL MUSEUM Vol. 67, aet. 82 



, EXPLANATION OF PLATES 



Zarhachis flagellator Cope. Cat. No. 10,911, division of vertebrate paleontology, 

 United States National Museum. Calvert formation, western shore of Chesa- 

 peake Bay, about 3% miles south of Chesapeake Beach, Calvert County, Md. 

 Collected by Norman H. Boss, December 30, 1923. 



Plate 1 



Dorsal view of skull of Zarhachis flagellator Cope. About ^ natural size. 

 The following abbreviations are used on plates 1 to 5. Bo., basioccipital; Bs., 

 basisphenoid; C, condyle; Cr. I., lambdoid crest; Cr. max., maxillary crest; 

 Ed., ectethmoid; Ex. oc, exoccipital; Ex. pt., external reduplication of the 

 pterygoid; Ex. aud. M., groove for external auditory meatus; Fal. pr., falcate 

 process of basioccipital; F. m., foramen magnum; Fo. c, condylar foramen; 

 Fo. inf., ventral orifice of infraorbital canal; Fo. I. p., foramen lacerum posterius, 

 compartment for vein; Fo. max., maxillary foramen at posterior extremity of the 

 premaxilla; Fo. ov., foramen ovale; Fo. pmx., premaxillary foramen; Fr., frontal; 

 /. inc., jugular incisure; Max., maxilla; A'^. A., left nasal passage; Na., nasal; 

 Pa., parietal; Pmx., premaxilla; Poc. pr., paroccipital process of exoccipital; 

 P. pr., postglenoid process of squamosal; Prs., presphenoid; Pt., vaginal process 

 of pterygoid; S. oc, supraoccipital; S. or. pr., supraorbital process of frontal; 

 Sq., squamosal; Vo., vomer; Zyg., zygomatic process of squamosal; 1, foramen 

 in alisphenoid above the anterior process of the periotic; 3, passage for mandibular 

 branch of trigeminal nerve in a cleft on posterior border of aUsphenoid; S, 

 foramen lacerum posterius, compartment for nerves, 



Plate 2 



Frontal view of skull of Zarhachis flagellator Cope showing position of the 

 crescentic foramina. About ^ natural size. 



Plate 3 

 Posterior view of skull of Zarhachis flagellator Cope. About K natural size. 



Plate 4 

 Lateral view of skull of Zarhachis flagellator Cope. About }^ natural size. 



Plate 5 

 Ventral view of skull of Zarhachis flagellator Cope. About K natural size. 



18 



