106 ]ME. W. H. FLOWER ON THE OSTEOLOGY OF 



compared with the forearm, and in the absence of the olecranon process. In the 

 carpus, to judge by Eschricht's figure, some differences of detail may be found. They 

 agree in the comparative length and slenderness of the phalanges and spread of the 

 fingers; but Platanista differs from Inia and all the other Dolphins in the nearly 

 equal development of the four outer digits, giving the remarkable truncated form to 

 the termination of the extremity. 



The pelvic bones have unfortunately not been preserved with the skeleton. They 

 are also unknown in Platanista. 



II. On the Skull of Pontoporia blainvillii. 



In the Museum at the Jardin des Plantes, Paris, is the skull of a small Dolphin 

 brought by M. de Freminville, an officer in the French navy, from the neighbourhood 

 of Monte Video, at the mouth of the Eio de la Plata. This was first described by 

 Professor P. Gervais, in the ' Bullet, de la Soc. Philomathique de Paris,' 1844, (27 AvtII) 

 p. 38, as Delj)Jii7ius Blainvillei ; also in ' ITnstitut,' of the same year. 



In the part of the ' Zoology of the Voyage of the Erebus and Terror ' devoted to 

 the Cetacea, published in 1846, Dr. Gray gave a figure and brief description of this 

 skull, and constituted the genus Pontoporia for the reception of the animal to which it 

 belonged. 



Professor Gervais, in the description of the " Mammiferes " of d'Orbigny's ' Voyage 

 en Amerique Meridionale,' published in 1847, but the introduction to which bears the 

 date of December 1846, redescribed and figured the skuU (plate 2.3), pointing out 

 that its peculiarities were sufficient to entitle it to rank as a subgenus, for which the 

 name of StenodelpMs was proposed. In the same plate a figure is given of a long- 

 beaked Dolphin, observed by d'Orbigny off the coast of Patagonia, but of which no 

 portion was brought home ; and a conjecture is thrown out that this Dolphin belonged 

 to the same species as the skull presented to the Museum by M. de Freminville. 

 Although this is a mere assumption, and not a very well founded one, as even the 

 colour does not correspond with the brief description given by M. de Freminville*, it 

 has unfoitunately been treated as a certainty in most systematic worksf, and thus Pon- 

 tojioria, the skull of which shows such near affinities with those of the river-Dolphins 

 Inia and Platanista, and which from its only known habitat may be wholly or partially 

 fluviatile, and of which the external form is entirely unknown, is now regularly installed 

 in zoological literature as an oceanic Dolphin with a high falcate dorsal fin ! 



A few weeks ago, and after the whole of the foregoing description of the skeleton of 



* " D'apres un renseignement favori par M. de Freminville, le Dauphin dont provient ce crane, est long de 

 quatre pieds, et il est blanc, avec une bande doreale noire." 



t See Gervais, Hist. Nat. des Mammiferes (1855), vol. ii. p. 322; Gray, Cat. Seals and Whales, Brit. Mus. 

 (1866) p. 231. 



