NO. 9 



NEW RIVER-DOLPHIN FROM CHINA MILLER 



The form of an entire tooth from near middle of toothrow (fig. i, 

 a, b) is strikingly different from that of a corresponding tooth of Inia 

 (fig. I, c, d). It more nearly resembles that of the teeth from the 

 Miocene of Maryland figured by Cope (Amer. Nat., Vol. 24, p. 607, 

 July, 1890) as those of Rhabdosteus but later referred by True 

 (Proc. Acad. Nat. Sci., Philadelphia, 1908, p. 29, April 22, 1908) to 

 Schisodelphis. The root through the greater part of its extent is not 

 conspicuously wider than the crown. It is compressed laterally, 

 while the crown is compressed antero-posteriorly. Between the root 

 and crown there is a distinctly indicated neck, but this constriction is 



Fig. I. — a. Lipotes vexillifer, i6th maxillary tooth, b. Lipotes vexillifer, 

 i6th mandibular tooth, c. Inia gcoffrensis, 15th maxillary tooth, d. Inia 

 geoffrensis, 13th mandibular tooth. All figures natural size. View at left of 

 each pair is from inner side, that at right is from behind. The teeth of Inia 

 are worn away at tip. 



neither so long nor so well developed as in the Maryland Schizo- 

 delphis,^ At base, the most compressed region, the root abruptly 

 widens to form a sharply defined anterior and posterior projection, 

 the combined function of which is to anchor the tooth firmly in the 

 alveolus. At first sight these projections suggest the final remnants 

 of two fangs completely joined through the greater part of the root, 

 but sections of that part of the tooth fail to reveal any traces of 



' It seems very doubtful whether these teeth should be referred to the same 

 genus as those figured by Probst (Jahreshefte Ver. vaterland. Naturk. Wiirt- 

 temberg, Vol. 48, pi. 3, figs. 11-14, 1886) from Wiirttemberg, Germany. 



