66 



THE QUARTERLY REVIEW OF BIOLOGY 



found in the coarse green quartz sands 

 at Eggenburg, north of Vienna, Austria 

 (Abel, 1899), in the sand pits near Belluno, 

 Italy (Dal Piaz, 1901, 1903, and 1905), 

 and the Uadi Faregh of Egypt (Stromer, 

 1905). The anterior teeth in both jaws 

 are elongated, with pointed, Unciform, 

 and laterally-compressed smooth-enameled 

 crowns, the anterior and posterior edges 

 being trenchant. These single-rooted 

 teeth are firmly implanted in distinct 

 alveoli, and the laterally compressed 

 roots are abruptly expanded below the 

 crown, forming a blade, which in some 

 teeth is directed almost at right angles 

 to the perpendicular axis of the crown. 

 Posteriorly the teeth little by little di- 

 minish in height. The inwardly curved 

 crowns become more conical with minute 

 tubercles on inner side at base, and the 

 roots less compressed and often thickened 

 below the crown. The implantation of 

 the teeth is oblique, and there were 

 something like 50 teeth on each side in 

 each jaw. The elongated rostrum is at 

 least equivalent to three-fourths of the 

 total length of the skull. The skull is 

 further characterized by a rather flat ver- 

 tex with relatively large exposure of the 

 frontals, a small rhomboidal interparietal, 

 and small antero-posteriorly compressed 

 nasals; a low supraoccipital; rostrum with 

 closely approximated premaxillaries, 

 ankylosed together dis tally with age, and 

 tapering less abruptly than the maxil- 

 laries; and olfactory foramina are present. 

 The dorso-ventrally compressed and solidi- 

 fied symphysis is equivalent to two-thirds 

 of the total length of the mandible, with 

 a longitudinal ventral furrow on each 

 side into which vascular foramina open. 

 The skeleton is known to contain 7 

 separate cervical and 10 dorsal vertebrae. 

 The Lower Miocene porpoise Cyrto- 

 dtlphis offers some points of unusual inter- 

 est. Its skull was not only telescoped to 



a high degree, but also its complement of 

 teeth has increased four or five fold above 

 the normal eutherian dentition. Cyrto- 

 ddphis proved sufficiently adaptable to 

 environmental conditions to leave de- 

 scendants in succeeding pelagic faunas, 

 and its several species have been found 

 in the Helvetian stage of France, the 

 Tortonian Calvert formation of Maryland 

 (True, 1908), the Sarmatian of Heiligen- 

 stadt near Vienna (Abel, 1899), the 

 Anversian of Antwerp, Belgium (Abel, 

 1905), and the supposedly more recent 

 Bone Valley formation of Florida (Allen, 

 192.1). 



Another equally interesting porpoise 

 from the Libano sand pit near Belluno has 

 recently been described by Dal Piaz (1916) 

 as Eoplatanista italica. The distinguished 

 Italian palaeontologist considered this 

 extinct porpoise to be a precursor of the 

 living Platanista and cited the peculiari- 

 ties of the teeth to support his contention. 

 Without attempting to go into an exten- 

 sive discussion of Eo-platanista italica and 

 follow out each structural detail, it may 

 be said that one can not well avoid being 

 cognizant of the resemblance of this 

 skull to the contemporary Cyrtodelphis. 

 Similarity of structure, such as observed 

 in these two extinct porpoises, can hardly 

 be considered superficial. In so far as 

 the cranium is concerned, Eo-platanista 

 differs from Cyrtodelphis in having the 

 vertex noticeably contracted in an antero- 

 posterior direction and a reduced number 

 of teeth, there being 40 teeth in each upper 

 jaw and 38 in each lower jaw. Otherwise 

 the contours and structural peculiarities 

 of the skulls of these two porpoises are 

 practically identical. The same observa- 

 tion holds true for the periotic bones. 

 That the type skull of Eoplatanista belongs 

 to an old individual is shown by the well 

 worn teeth, which are ground down to or 

 below the level of the base of the crown. 



