84 bulletin: museum of compaeative zoology. 



This last observation with respect to fusion between the tympanic and 

 periotic applies also to material obtained by the " Albatross" Expedition, 

 and it is interesting to note that some specimens still have the stapes 

 preserved in its natural position. This is the more remarkable in view 

 of the fact that the stapes is not anchylosed, but firmly held in place by 

 muscular attachment within its proper aperture, the fenestra ovalis. 

 We will return to a description of the different parts furtlier on. 



The question is apposite whether any certain identifications can be 

 made between these deep-sea remains and fossil or recent Cetaceans. In 

 the case of the " Albatross " material it must be acknowledged that no 

 specimens can be positively referred to extant species. The differences 

 they present are all of minor nature, and yet sufficient in the aggregate 

 to make it extremely hazardous to pronounce in favor of absolute iden- 

 tity. One may safely affirm that the bones here referred to Kogia and 

 Hyperoodon differ specifically from K. breviceps and H. rostratus, but 

 as for undertaking comparisons with other existing representatives of 

 these genera, there is not only great lack of material, but the published 

 descriptions and illustrations are singularly inadequate. Confusion 

 exists as to what species should be properly retained in the former genus, 

 and the second known species of Hyperoodon^ H. planifrons rests upon 

 the evidence of a solitary water- and pebble-worn skull. On the other 

 hand, a number of well preserved fossil ear-bones of Hyperoodon are 

 available for comparison, which will be referred to later, but none have 

 hitherto been found of the genus Kogia. The range of comparison 

 amongst fossil Delphinoid remains is limited, since most of the extinct 

 forms belong to tlie Platanistid division, and hence are not properly 

 classed with true Dolphins. The affinities of the deep-sea ear-bones seem 

 to be rather with the Delphinidae proper, and some of them show con- 

 siderable resemblance with those of the existing Delphinus delphis Linne 

 {cf. Plate 3, Figs. 30-32). 



The conclusions just stated all have reference to the "Albatross" 

 material. Turning now to that obtained by the "Challenger," we find 

 identifications made with four existing species, whose remains, however, 

 were all dredged from more southerly areas than were visited by the 

 "Albatross." The greater number of "Challenger" ear-bones are be- 

 lieved by Professor Sir William Turner to belong to extinct forms, his 

 remarks on this subject being as follows : ^ 



The sharks' teeth belonged to the genera Carcharodon, Oxyrhina, and Lamna, 

 and are to be referred to no species, so far as we know, now liring. The question 



1 Loc. cit., p. 42. 



