38 SYSTEMATIC PALEONTOLOGY 



premaxillary and maxillary elements. This point of attachment is, 

 however, anterior to that of any known genns of Mysticete; and is 

 anterior to that in the Agoropliius pygmcsus Mlill. In not extending 

 so far posteriorly as the nasal bones, it leaves the frontals to embrace 

 the latter anteriorly to an unusual extent. This is on the supposition 

 that the indistinct grooves on each side of the middle line really repre- 

 sent the lateral borders of the nasal bones, which is not certain, except 

 as to their anterior portions. 



Measurements. 



mm. 



Width of skull at exoccipitals 406 



Width of skull at postgienoid angles 570 



Width of occipital condyles 150 



Width of foramen magnum 65 



Width of sagittal crest 17 



Width of anterior border of nasal bones 90 



Width of skull at sagittal crest 170 



Width of sphenoid at middle of for. lacerum 135 



Anteroposterior diameter of glenoid surface 115 



Length of nasal canal 250 



Length from occipital condyles to anterior nares 450 



Length from foramen magnum to posterior end of sagittal 



crest (oblique) 310 



Length of sagittal crest 15 



Length from sagittal crest to anterior nares 195" 



Cope, 1896. 



Occurrence. — St. Mary's Formation. Near the mouth of the Po- 

 tomac river. 



Collection. — Museum of the Woman's College of Baltimore. 



Genus CEPHALOTROPIS Cope. 



" Char. gen. Parietal bone separating supraoccipital and frontal by 

 a considerable space and presenting a sagittal crest. Frontal exten- 

 sively overlapped by the maxillaries, premaxillaries and nasals. Nasal 

 elongate, distinct from the adjacent elements. Frontals presenting 



