ON THE OCCURRENCE OF REMAINS OF FOSSIL CETA- 

 CEANS OF THE GENUS SCHIZODBLPHIS IN THE 

 UNITED STATES, AND ON PRISCODBLPHINUS ( ?) 

 CRASSANGULUM CASE 



By FREDERICK W. TRUE 



Head Curator of Biology, U. S. National Museum 



(With two plates) 



In 1904 Mr. E. C. Case described in the Report of the Maryland 

 Geological Survey 1 a skull of a fossil porpoise, which he assigned 

 provisionally to the genus Priscodelphinus, as a new species, under 

 the name of Priscodelphinus ( ?) crassangulum. The type specimen 

 was obtained on the shore of Chesapeake Bay, three-fourths of a 

 mile north of Governor's Run, Calvert County, Maryland, from the 

 Miocene marl belonging to the Calvert formation. The type con- 

 sists of the rostrum of the skull, nearly complete, a part of the basis 

 of the skull, one zygomatic process, one occipital condyle, a tympanic 

 "bulla, and the mandible, which is nearly complete, but lacks the con- 

 dyles. In addition, a large fragment, which resembles the orbital 

 process of the frontal, is present, but, as will be explained later, I 

 have been unable to satisfy myself that it is really such. Among 

 other fragments, which I have been unable to identify positively, are 

 some which appear to represent the thin portions of the pterygoids. 

 No teeth were preserved. The rostrum, mandible, basis cranii, 

 zygomatic process, occipital condyle, and tympanic bulla were figured 

 by Mr. Case. 2 



While studying the types of various fossil cetaceans in the collec- 

 tions of Johns Hopkins University and of the Maryland Geological 

 Survey, I was permitted by Prof. William B. Clark to bring the type 

 of Mr. Case's species to Washington, where it has been put together 

 under my direction. As Mr. Case's figures are from drawings, I have 

 thought it desirable to supplement them by figures reproduced from 

 photographs. 



Before considering this valuable specimen in detail, I desire to make 

 certain observations regarding the genus Priscodelphinus. The genus 

 was established by Leidy in 1851 or 1852 3 on the basis of a dorsal 



'Report of Maryland Geological Survey, Miocene, text, 1904, p. 12, pi. 11, 

 figs. 1-3. 



2 Op. cit., pi. 11, figs. 1-3. 



3 Proc. Acad. Nat. Sci. Phila.. 5, p. 326. Read Dec. 9, 1851. 



449 



