290 Prof. Eschricht on the Gangetic Dolphin. 



nearest of all, namely the Amazon dolphin, or D'Orbigny's genus 

 Inia (alluded to above, p. 280), where we have quoted a work of 

 Andr. Wagner, in which he proves satisfactorily that this remark- 

 able animal was first mentioned by Desmarest, was next brought 

 to Europe by Spix and Martins, and lastly that it was described 

 by D^Orbigny. The similarity is not only indicated by its river 

 habitation, but also in its exterior form, because like our animal 

 the dorsal fin is very low, and the beak long and toothed. But 

 as far as the last-mentioned naturalist^s very incomplete account 

 and figure enable us to judge, none whatever of the peculiarities 

 in the cranium of the Gangetic dolphin are found in the Amazon 

 species ; the teeth are totally different ; the eyes can scarcely be 

 called small. If I consider Messrs. Gray and Wagner^s placing 

 the two animals together as plausible, it is done chiefly in the 

 expectation, that further researches may discover points of agree- 

 ment also in the internal parts. 



Taking a retrospective view of the series of coincidences and 

 discrepancies in the structure and mode of life of the Gangetic 

 dolphin, as compared on the one hand with those of the Hyper- 

 oodons, on the other with the Whitefish, and lastly the Amazon 

 dolphin, — keeping before us its absolute peculiarities, that is, its 

 rudimentary eye and its blowhole in the shape of a longitudinal 

 fissure — we have a variety of diff"erences in form, strongly con- 

 trasting with the commonly admitted uniformity of structure and 

 mode of living of Cetacea. If we try to place it among the 

 toothed whales, we cannot hesitate to constitute it into a se- 

 parate genus, Platanistay nearest between the Hyperoodons and 

 the Whitefish, the former of which are again close to the Cachalot 

 (all having the shape of the jaws and the tongue of our animal) ; 

 while the Whitefish approaches closest to the Narwhale, and next 

 to Delphinus globiceps ; but on the other hand, it must probably 

 not be removed far from the Amazon dolphin, though the two 

 can hardly be placed under one common group {Platanistina of 

 Gray) . In my sixth Memoir on Whales, I have endeavoured to 

 prove in detail, by means of a series of researches into the osseous 

 structure of the Hyperoodon, as compared with the short-finned 

 dolphins {Micropteron) , and the extinct species of Cuvier's 

 Ziphius, that these whales are closely allied among each other. 

 I have since had opportunities still further to corroborate those 

 observations/especially with reference to the so-called Delphinus 

 Sowerbyensis, which I have insisted on was only the male Micro- 

 pteron. The cranium of Sowerby's valuable specimen, deposited 

 in the anatomical museum of the University of Oxford, was re- 

 ported by Mr. Gray as no longer existing there, and therefore 

 reference was had to a drawing formerly made of it, and of 

 which he has given a copy. It was therefore a very gratifying 



