8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



internal structures to support this view. In the teeth at the extremi- 

 ties of the toothrows the anterior projection is less developed. The 

 resulting form suggests that of some of the teeth from the upper 

 Miocene of northern Italy figured by Dal Piaz under the name 

 Cyrtodelphis sulcaUis (Palseont. Ital, Vol. 9, pi. 31, 1903). In the 

 median teeth of Inia (fig. i, c, d) the root is expanded to about 

 double the diameter of the crown. The basal projections, though 

 present and efficient in retaining the teeth in the socket, are masked 

 by the general widening. 



Remarks. — The genus Lipotes differs too widely from its only 

 known living relative, Inia, to require special comparisons beyond 

 those which have already been made. Externally its most conspicu- 

 ous peculiarity is the presence of the large triangular dorsal fin. In 

 the skull many of the differences between the two animals are corre- 

 lated with the opposite curvature of the beaks. Opposite tendencies 

 are also to be observed in the teeth, those of Inia having specialized 

 on strength and robustness, those of Lipotes on wideness of grasp 

 (compare especially the palatal aspect of skull shown in plates 6 

 and 7). 



Among the described fossil dolphins there appears to be no genus 

 whose relation to Lipotes is especially intimate. Reference has 

 already been made to the likeness of the teeth to those of the Ameri- 

 can Schizodelphis. There is also a noticeable similarity between 

 the base of the beak and that of Pontistes as figured by Burmeister, 

 but this is obviously a chance resemblance as Pontistes is no longer 

 regarded as one of the Iniidcc. 



LIPOTES VEXILLIFER, sp. nov. 



Type. — Skull and cervical vertebrse of adult male, No. 218293,. 

 U. S. National Museum. Collected in Tung Ting Lake, China,, 

 February 18, 1916, by Charles' M. Hoy. 



Diagnosis. — A porpoise about two and one-half meters in length, 

 greatest length of skull about 500 mm. ; color pale blue-gray above, 

 white below. 



Measurements. — Cranial measurements of type. Condylobasal 

 length, 514 (526)'; basal length, 510 (515) ; from middle of supraoc- 

 cipital to tip of beak, 481 (497) ; rostrum, 350 (352) ; distance from 

 tip of beak to nares, 390 (403) ; distance from last tooth to apex of 



^ Measurements in parentheses are those of a somewhat older skull of Inia 

 geoffrcnsis. No. 49582, U. S. National Museum. 



