ART. 26 REMAINS OF FOSSIL PORPOISES KELLOGG 33 



All of the material that could be found was brought to Washing- 

 ton, and thanks to the skillful manner in which the fragments have 

 been fitted together by Norman H. Boss, a fair skull was made avail- 

 able for study. In its present condition the loss of the extremity 

 of the rostrum is the most noticeable defect. Fortunately the ex- 

 ternal margins of the maxillae above the temporal fossae are perfect 

 and supplement the skull of individual 1 (Cat. No. 8842, U. S. Nat. 

 Mus.). The premaxillae were damaged in the region of the nasal 

 passages and the missing portions have been restored. There is an 

 unusually deep external groove leading backward from the pre- 

 maxillary foramen. The nasal bones are in contact mesially for 

 a distance of 25 mm. The exposed portions of the frontals on the 

 vertex are relatively narrow and are not noticeably longer than the 

 nasals. The dorsal surface of the vertex (pi. 16, fig. 1) is higher 

 than the adjoining upper margin of the supraoccipital. On the 

 left side the posterior half of the supraorbital process is missing. 

 The left zygoma lacks the postglenoid process and a portion of its 

 anterior extremity. Except for the anterior end, the right zygoma 

 is lost. In addition the lower half of the left exoccipital and the 

 adjoining portion of the descending plate of the basioccipital are 

 missing. In the region of the temporal fossae, both parietals are 

 absent. The pterygoids (pi. 1.5, fig. 2) are completely destroyed on 

 the left side. On the right side, a small portion of the internal plate 

 of the pterygoid which abuts against the basisphenoid is present; 

 the remainder of this plate and its external reduplication are miss- 

 ing. In consequence of the loss of the external plate of the ptery- 

 goid, the optic canal is exposed near its origin. Because of the 

 absence of the mesethmoid and the loss of the internal plates of the 

 pterygoids, the nasal passages do not appear as small as they do in 

 better preserved skulls. The foramina (pi. 5) in the right tympano- 

 periotic recess are well preserved; those on the left side are more 

 or less mutilated. A broad strip of the supraoccipital extending 

 from side to side immediately above the foramen magnum is also 

 missing. The posterior styliform processes of the jugals are miss- 

 ing on both sides, but their anterior extremities are present. For 

 the most part the septa between the alveoli are obliterated. 



Occurrence. — Near latitude 38° 40' north, and longitude 76° 41' 

 west, South Chesapeake Beach, on the western shore of Chesapeake 

 Bay, Calvert County, Maryland. Shown on Patuxent Quadrangle or 

 Patuxent Folio, No. 152, United States Geological Survey. 



Horizon. — This skull came from Shattuck's zone No. 3 of the Cal- 

 vert Miocene formation of Maryland. It was discovered and exca- 

 vated by William Palmer in September, 1920. 



