186 Prof. Eschricht on the Gangetic Dolphin. 



caudal, in contradistinction to the 14 anterior, or caudal proper. 

 My reason for this distinction is, that, while in all 5 the an- 

 terior, or proper caudal vertebrae, the processes of the lumbar 

 vertebrae are still found to exist, with the exception of the arti- 

 cular, which we have noticed as disappearing already in the last ; 

 they are wanting in all the subsequent ones ; and in lieu of them 

 a new series of marked processes makes its appearance, develop- 

 ing itself gradually along the anterior caudal vertebrae. The 

 bodies of these increase, accordingly, in thickness until the 7th ; 

 from thence they diminish again, most perceptibly so from the 

 12th. But the arc part, with the spinous and mammillary pro- 

 cesses, diminish through the whole series, only a vestige remain- 

 ing in the last, in the shape of a very small low bridge. It will 

 be seen in the figure (PI. V. fig. 2), that in this gradual disap- 

 pearance, the spinous processes become proportionally broader 

 (rather larger in the direction of their length) and the mam- 

 millary proportionally thicker, both at the same time moving 

 more downwards. 



Looking now to the haematapophyses, or the lower vertebral 

 arcs, we find the first of these (between the 27th and 28th ver- 

 tebra?), as so often happens in Cetacea, wide open, in other 

 words, divided into its two lateral portions ; and at the same time 

 quite un symmetrical. It is short and broad on the left side 

 (PI. V . fig. 2), its lower margin scarcely extending under the 

 body of the next following vertebra ; while on the right side it 

 is not only placed somewhat more backwards, but its lower por- 

 tion extends quite into and attaches itself to the second haemata- 

 pophysis. The third is the longest; the succeeding ones de- 

 crease gradually, and the 14th, between the 40th and 41st ver- 

 tebrae, appears only as a cartilaginous arc, 2'" to 3'" in height (sur- 

 rounding the probably very small caudal artery), with an osseous 

 nucleus in each side part. These haematapophyses, it is known, 

 embrace the large caudal artery, which is an elongation of the 

 aorta, a large branch of which ascends on both lateral surfaces of 

 the body of each vertebra. This branch proceeds in the first eight 

 caudal vertebrae behind the transverse process, in the five sub- 

 sequent ones through it. Its furrow gets gradually deeper behind; 

 the transverse processes in the meantime decreasing by degrees so 

 much in height, that from the 9th to the 12th vertebrae they ap- 

 pear as a broken, but on the 13th as an entire little bridge. 

 From the last proper caudal vertebra the arterial branch de- 

 scends still deeper into the body of the vertebra. In the mean- 

 time two other lines of processes make their appearance in the 

 caudal series of vertebrae, which I cannot consider as processus 

 accessorii, although there exist no others which correspond to 

 these. I propose terming them processus caudales. They have the 



