NO. 9 NEW RIVER-DOLPHIN FROM CHINA MILLER 5 



Cervical vertebra. — The cervical vertebrae (pis. ii and 12) while 

 agreeing with those of Inia (pis. 11 and 13) in the complete sepa- 

 ration of all the bones of the series dififer from those of the South 

 American dolphin in so many details of form, some of which may 

 prove to be subject to individual variation, that a complete enumera- 

 tion of the peculiarities will not be undertaken. The more general 

 differences, among those which appear to be of importance, are as 

 follows : In Inia the lateral canal is open behind the third vertebra ; 

 in Lipotes it is essentially closed throughout. In Inia the centra and 

 the neural openings tend to be higher than wide ; in Lipotes wdder 

 than high. In Inia the neural spine is large and high in both second 

 and seventh vertebra ; in Lipotes it is broad and low in the second, 

 scarcely developed in the seventh. In Inia the lower transverse proc- 

 ess of the fourth vertebra is enlarged and curved forward ; in 

 Lipotes it is reduced and curved backward. In Inia the lower trans- 

 verse process of the fifth vertebra is straight and greatly enlarged ; in 

 Lipotes it is curved forward and slightly enlarged. In Inia the lower 

 transverse process of the sixth vertebra is reduced ; in Lipotes it is 

 the largest of the series. In Inia the seventh vertebra has no lower 

 transverse process ; in Lipotes the lower transverse process is fully 

 developed, its extremity joined to the upper process. Further com- 

 parison will be found below : 



First Cervical 



Lipotes Inia 



Basal process slightly developed, its Basal process large, its length about 



length not equal to longitudinal diam- twice as great as longitudinal diameter 



eter of centrum. of centrum. 



Upper transverse process an incon- Upper transverse process a con- 

 spicuous ridge on base of pedicle. spicuous knob below base of pedicle. 



Second Cervical 



Spinous process with upper-anterior Spinous process with anterior mar- 

 margin sloping gradually and in gin sloping very abruptly and forming 

 approximately the same line as that a conspicuous angle with that of first 

 of first cervical. cervical. 



Transverse process narrow and Transverse process broad and 



long, partly or completely perforate. short, imperforate. 



Third Cervical 



Neural arch open above. Neural arch closed above. 



Transverse processes long, united. Transverse processes short, sepa- 



their extremities nearly at level of rate or nearly so, their extremities 



lower border of centrum ; lateral about at level of centrum ; lateral 



canal relatively small. canal relatively large. 



