34 THE VOYAGE OF H.M.S. CHALLENGER. 



not unfrequently broke up into fragments, for their texture and cohesiveness were often 

 greatly injured ; but at times Mr Murray bad succeeded in removing the whole of the 

 manganese from the exterior of the bone, so as to enable one to study its form. 



In the catalogue of the dredgings which has been compiled for the use of the 

 naturalists engaged in describing the animals collected during the voyage of the Chal- 

 lenger, the stations at which the dredge was put down are all designated numerically, and 

 the latitude and longitude are recorded, so that the locality can be determined on the 

 map ; the date when the dredging took place, and the depth of the ocean at the spot are 

 also given. I have extracted from this catalogue these important facts in connection with 

 the description of the cetacean bones obtained at each station. 



The stations are numerically arranged according to the dates when the dredgings 

 were done, but instead of taking the first at which cetacean bones were observed, it will 

 be more convenient to start with the description of the station where the largest number 

 and the greatest variety of the bones of these animals were brought to the surface. I 

 shall commence, therefore, with a description of the bones found at Station 286. 



Station 286, lat. 33° 29' S., long. 133° 22' W., October 16, 1875, 2335 fathoms. 

 This station was remarkably rich in cetacean remains. About ninety tympanic bullas 

 were recognised, and, in addition, there were various fragments coated and imbedded in 

 peroxide of manganese, many of which appeared to be portions of tympanic bones. In 

 the first place I made a rough classification of these bones according to their size, and 

 found that they could be arranged into five groups. 



The first group was represented by a single sj)ecimen nearly 6 inches long, and 

 by a fragment of another, which had apparently been of the same magnitude. They 

 were impregnated with manganese, and much corroded on the surface. The more 

 perfect specimen had been cut in two, and one half sent for chemical analysis before 

 I saw it ; but from the half that remained I judged it to have been about the same size 

 as the tympanic bone of the great Northern Eorqual [BalcBnoptera sibhaldi), stranded 

 at Longniddry, which I described some years ago.^ A section through this bone is 

 figured by Mr Murray in his Report on deep-sea deposits (PI. VII. fig. 2). On comparing 

 it with the corresponding tympanic bone of this animal, they were seen to have a 

 somewhat similar general configuration, but the corrosion of the surface of the deep-sea 

 specimen prevented a close comparison being instituted. From the magnitude of the 

 specimen, it is probable that it is the tympanic bulla of a great Southern Rorqual, perhaps 

 the BalcBiioptera antarctica, or a closely-allied species. 



The second group consisted of fifteen tympanic bullae, varying in size from 3 inches 

 to 4 inches, but these were divisible into two very distinct types. 



In the one type, consisting of the somewhat larger specimens, were two admirably- 

 preserved bones with the deposit of manganese so thin that the form of the bone was not 



1 Trans. Roy. Soc. Edin., Nov. 1870, vol. xxvi. 



