Prof. Eschricht on the Gangetic Dolphin. 283 



points it out as a strong swimmer, the spinous as well as trans- 

 verse processes serving, even in the lumbar region, for the inser- 

 tion of the muscles of the tail, by which the body is propelled 

 through the water ; and the short and unbending tail is an 

 essential condition for securing to the head and the whole body 

 with it, a ready propulsion through the waves of the sea. The 

 Gangetic dolphin, on the contrary, is distinguished as a cetaceous 

 animal, by having a limited power of swimming, combined with 

 a certain degree of motion of the head and its long and pointed 

 beak. If we desire to trace these peculiarities of the Platanista 

 skeleton among other groups of whales, we shall soon and easily 

 recognise them in the Whitefish and the nearly allied Narwhale ; 

 the former having fifty-one vertebrae (the latter fifty-two), with 

 eleven pairs of ribs (in the latter there is an imperfect twelfth 

 pair) ; the Narwhales having a proportionally long neck ; and 

 their cervical vertebrae (at least in the Whitefish) being never an- 

 chylosed, but always connected by means of joints *. There is 

 another remarkable circumstance, namely, that the processus 

 odontoideus in the Whitefish is, next after our dolphin, more 

 clearly developed than in any other member of the order ; it has 

 however the same form, the obliquely truncated articulating sur- 

 face, directed rather towards the head than to the ventral surface, 

 as in the Gangetic dolphin. Not only in regard to the neck, 

 but also in other regions of the skeleton, is our dolphin nearest 

 allied to the Whitefish. Its vertebrae are much fewer in number 

 (fifty-one) than in the proper dolphins generally (the long-jawed, 

 many-toothed) ; greater than in the Hyperoodons and even in 

 the small Finwhales, equalling exactly the number in the White- 

 fish (the Narwhale having an additional pair of vertebrae). The 

 pairs of ribs (eleven) are more numerous than in the Hyper- 

 oodon, but precisely as in the Whitefish (the Narwhale having 

 usually a twelfth pair, though it is disproportionally short). Of 

 far greater importance is the similarity in the form of the ver- 

 tebrae, which, in the Hyperoodon, as in the proper Dolphins, are 

 distinguished by the remarkably high spinous processes, particu- 

 larly in the thoracic vertebrae, while in our dolphin they are low, 



* This is what I have seen in all the Whitefish skeletons examined bv 

 me ; and as far as I know, no one else has found it otherwise. Occasionally 

 a pair of the foremost cervical vertebne are found connate in the Narwhale ; 

 in the Vaagehval sometimes the second with the first or third. But these 

 varying ossifications belong by no means exclusively to old skeletons ; and 

 they cannot therefore serve as an argument in favour of the entirelv un- 

 founded assumption, at least as a general one, that growing together of the 

 cervical vertebra: in whales, is the effect of age. I shall be able to prove in 

 a future Memoir on "Whales i the seventh in the series), as the result of long- 

 continued inquiries, that the normal combination of these vertebra;, already 

 -shows itself, in most species of whales, while still in the state of cartilage. 



19* 



