REPORT ON THE CETACEA. 33 



These bones are evideDtly a portion of the skeleton of the Balcena or EuhalcBna 

 australis. In their form and appearance they closely corresj)ond to the block of cervical 

 vertebrce, figured by Van Beneden and Gervais, in Plates I. and II. fig. 19, as the cervical 

 vertebrae of that animal. M. Van Beneden states that in Balcena australis there is no 

 trace of inferior transverse processes in the last four cervical vertebrae, and that this 

 constitutes a noticeable point of diff"erence between this species and the Balcena 

 antipoclarum, in which aU the cervical vertebrae, except the seventh, have an inferior 

 transverse process. In the Challenger specimen, the inferior transverse process was 

 absent in the seventh, sixth, and fifth cervical vertebrae, but present in the fourth, third, 

 and second, so that in the presence of this process in the fourth vertebra, it diff'ered 

 from the specimen described and figured by M. Van Beneden. I am inclined to think 

 from the ajDpearance of his figure, that his specimen must have been from a younger 

 animal, as the lines of demarcation between the spines and laminae of the vertebras 

 are more distinct than in the Challenger specimen, and the first dorsal vertebra is not 

 ankylosed to the seventh cervical. The absence, therefore, of an inferior transverse 

 process in the fourth vertebra in M. Van Beneden's animal, may, perhaps, be due to the 

 ossification not having advanced to a stage so far as was the case in the Challenger 

 specimen. 



Cetacean Bones dredged from the Bed of the Ocean (PL IL). 



The dredge brought up in various localities, from a great depth, numerous tympanic 

 and petrous bones of Cetacea, together with fragments of other bones of the skeleton. 

 They have been aU carefully picked out by Mr John Murray from the other contents of 

 the dredge, and arranged according to their locality, and the depth at which they were 

 obtained. The conditions under which they were found will be described by Mr 

 Murray in his Report on the deep-sea deposits. At his request, and that of Sir WyviUe 

 Thomson, I undertook to determine, as far as possible, the generic and specific characters 

 of these bones, and have compared them with the collection in the Anatomical Museum 

 of the University of Edinburgh. In 1876 and 1879 I took a number of selected 

 specimens to the Museum of the Royal College of Surgeons of England, and, along with 

 Professor Flower, compared them with specimens in that magnificent collection. 



The bones were almost without exception coated with a brown material consisting 

 of a mixture of the peroxides of manganese and iron, along with earthy matters ; some- 

 times only with a thin layer, but at other times imbedded in masses of these minerals,^ 

 which frecpently assumed a nodulated or botryoidal arrangement, and the manganese 

 had also penetrated into their substance. In attempting to peel this material, which 

 for the sake of brevity will be spoken of as manganese, off the exterior of the bones, they 



' See Mr Murray's paper in Proc. Roy. Soc. EJiii., December 18, 1876, p. 257. 



(ZOOL. CHALL. EXP. PAET IV. 1880,) D 5 



