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



One ill size and config'uration like a Mesojdodon. Six separate petrous bones and four 

 separate tympanic bullae, either broken or so encrusted with manganese that it was 

 difficult to determine them precisely, but they were all from the smaller species of Cetacea. 

 There were several manganese nodules, one of which had for its nucleus a fragment of bone 

 the size of a thick wafer. 



Station 276, lat. 13° 28' S., long. 149° 30' W., September 16, 1875, 2350 fathoms. 

 Two tympano-periotic bones of Mesojjlodon closely resembling Mesojjiodon layardi, 

 figured by Mr Murray (PI. VII. figs. 6, 7). In addition there were eight separate 

 petrous bones and six tympanic bullae. One of these bullae was a Glohiocephalus ; 

 another had the same form as the two sjaecimens described at the end of the fifth group 

 of Station 286, one of which is figured in Plate II. fig. 14 ; the remainder belonged 

 apjDarently to the genus Delphinus. 



Station 281, lat. 22° 21' S., long. 150° 17' W., October 6, 1875, 2385 fathoms. 

 Six tympanic bones and three petrous bones. The largest tympanic was 1^ inch long, 

 the smallest 1 inch. They all belonged to the family of dolphins. 



Station 285, lat. 32° 36' S., long. 137° 43' W., October 14, 1875, 2375 fathoms. 

 This station gave one tympanic bone, 4'7 inches long, from a large species of Balcenoj^tera 

 (Mr Murray's, PL VII. fig. 1) ; one 3 "2 inches long, and two others about 2 "7 inches long, 

 from smaller species of Bcdcenoptera, such as are referred to in the second group of 

 Station 286. A tympanic bone, Z^ inches long, was not swollen out as in Bcdcenoptera, 

 but was much smaller than the bulla of either Megap)tera lalandi or Bcdcena australis. 

 This bone was imperfect, as the part of the outer aspect which turns over into the hollow 

 of the bulla was broken off". Uj)wards of twenty-five smaller sized, separated tympanic 

 bones, which may be referred to the genera Mesoplodon, Delphinus, and Glohiocephalus. 

 At least eighteen petrous bones recognisable as belonging to the above genera of toothed 

 whales. A petro-mastoid bone, 4 inches long, probably belonging to one of the Baleen 

 whales, but with its form obscured by manganese incrustations. Numerous small 

 fragments of bone thickly coated with manganese. 



Station 289, lat. 39° 41' S., long. 131° 23' W., October 23, 1875, 2550 fathoms. 

 Three large tympanic bones were obtained here ; one 4 inches long, another Z^ inches, 

 the third about 3 inches long. They were all thickly covered with nodulated manganese. 

 Sufiicient of this deposit was removed to show that they were all apparently the bullae of 

 whales of the genus BcdcBnoptera. Two nodules containing bony nuclei were also present. 



Station 293, lat. 39° 4' S., long. 105° 5' W., November 1, 1875, 2025 fathoms. 

 In this station only one small fragment of bone, the form of which was quite lost through 

 impregnation with manganese, was found. 



Station 299, lat. 33° 31' S., long. 74° 43' W., December 14, 1875, 2160 fathoms. 

 This station contained one bilobed tympanic bulla, with the petrous bone attached, 

 apparently a Glohiocephcdus. 



