MIOCENE PORPOISES — KELLOGG 131 



The possibility exists, however, that one of the names given by either 

 Leidy or Cope to vertebrae or teeth from the Miocene formations of 

 Maryland or Virginia may be applicable to this previously unrecog- 

 nized long-beaked porpoise. Until a skull is found with at least some 

 associated vertebrae and teeth that are satisfactory for comparison 

 with these type vertebrae and teeth, the identity of some of the forms 

 described by Leidy and Cope will remain questionable. 



The porpoise hereinafter described was characterized by larger 

 teeth than any of the above mentioned long-beaked genera, although 

 the total length of the skull was unquestionably shorter. Compara- 

 tive measurements suggest that the total length of the skull did not 

 exceed 630 mm. Not one of the European Miocene porpoises hereto- 

 fore described agrees with the mandible of this Calvert porpoise in 

 essential characters. 



Three of the European forms, however, deserve some comment. 

 As regards the type mandible of Palaeoziphius scaldensis (Abel, 1905, 

 p. 91, fig. 15) which was found in the excavations at Antwerp in 

 deposits of Bolderian age, the alveolae, in addition to being slightly 

 larger (12 were located on the symphj^sis in an interval of 168 mm. 

 as compared to 16 on the mandible hereinafter described), appear also 

 to have been separated by thicker septa. Although the width (44 

 mm.) of the posterior end of the symphysis of Palaeoziphius scaldensis 

 is less than that (52.5 mm.) of this Calvert specimen, the variation 

 in the transverse diameter of both specimens 168 mm. anterior to the 

 posterior end of the sjonphysis is not more than 2 mm. The opposite 

 free hinder portions of the mandible of the Belgian Palaeoziphius form 

 an acute angle at the level where they ankylose as the symphysis, 

 whereas in the Calvert specimen the rami form a rather wide blunt 

 angle. In addition the anterior end of the symphysis of the Belgian 

 specimen is more noticeably bent upward and the furrow or groove 

 on the lateral surface of each ramus according to Abel is deep and 

 anteriorly bifurcated. The symphysis of this type mandible is incom- 

 plete anteriorly. 



The ankylosed mandibles found in a marl pit of Helvetian age at 

 Montfort near Dax, Landes Department, France, which constitute 

 the type of Champsodelphis lophogenius (Valenciennes, 1862; Type, 

 No. 11731, Lab. Paleont., Mus. Nat. Hist. Nat., Paris) are charac- 

 terized in part by a slightly narrower width (43.2 mm.) at the posterior 

 end of the symphysis, although the vertical diameter (42.6 mm.) of 

 the left mandible at the hindmost alveola is identical. However, the 

 angle (Van Beneden and Gervais, 1874, pi. 57, fig. 10a) formed by 

 the opposite mandibles behind the point where they ankylose to con- 

 stitute the symphysis is acute, in contrast to the more rounded angle 



