REPORT ON THE GET ACE A. 35 



iuterferetl with. The one bulla was 3 "6 inches long, the other was 3 "4 inches. They 

 closely coiTCsponded in size to the tympanic iDones of the northern pike whale {Balceit- 

 optera rostrata). The larger specimen also resembled in its configuration the biilla of 

 BalcBiioptera rostrata, it is figured by Mr Murray (PI. VII. fig. 3) ; the smaller was also 

 very like it on the external convex surface, but the internal surface, where it curved 

 towards the tympano-periotic fissure, was much more convex in the deep-sea specimen 

 than in the recent Balcenoptera rostrata. There can, I think, be no doubt that both 

 these specimens are from Cetacea of the genus Balcenopitera, and from an animal closely 

 allied to, if not identical with, the Balcenoptera rostrata of the North Atlantic Ocean. 

 It is possible that they may have belonged to the pike whale of the Southern Ocean, 

 named by Dr Gray, Balcenoptera huttoni, an animal which Dr Hector states,^ " is hardly 

 distinguishable from the northern Balcenoptera rostrata." 



Belonging to the same type of bullae, but not more than 3 inches or 3 "2 inches long, 

 were several buUse, all of which, with one exception, were thickly coated with manganese, 

 and the hoUow of the bulla was almost filled with it. They were not only shorter than the 

 bulla of BalcBuoptera rostrata, but not so swollen out (PL II. fig. 11). I am not aware of 

 any existing BalcBnoptera in which the biiUae have such small dimensions ; but in the 

 series of fossil ear-bones from the Eed Crag of SujBPolk, in the Museum of the Ptoyal 

 College of Surgeons of England, collected by Professor Flower, is a specimen marked 

 1452a;, which he is disposed to regard as a small Balcenop)tera, that agrees in size with 

 these specimens, and has a general resemblance in form, although difi"erenoes in the 

 smaller features of detail can be recognised. These bulla3 may have belonged to a 

 species of Balcenoptera no longer extant. 



The other type of bulla belonging to the second group consisted of two bones 3 

 inches in length. They were much more compressed laterally than was the case with 

 the l^uUse of the BalcBnopteridce, and were concave on the outer surface, but the inner 

 surface was almost entirely broken away, so as to expose the interior of the bulla. In 

 both specimens (obviously a pair) the outer surface was scored with elongated, some- 

 what curved furrows, as is represented in Plate VII. fig. 5 of Mr Murray's plates 

 on the deep-sea deposits. The general direction of these furrows corresponded with 

 that of the long axis of the tympanic bone ; but, though generally alike, they were not 

 quite symmetrical in the two buUas. In one specimen the grooved surface was completely 

 coated with a very thin layer of manganese, in the other only partially so. The fact, 

 however, that the manganese lined the grooves shows that they must have been imprinted 

 on the bones before the deposition of manganese began at the bottom of the ocean. 

 Whether they are natural marks, or artificially produced by the teeth of a fish or other 

 marine animal, it is difficult to say. These bones seem to belong rather to the type of 

 the Balceniclce than the BalcBnopteridce, though they are very much smaller than the 



^ Trans. New Zealand Institute, vol. x. p. 337. 



