REPORT ON THE CETACEA. 37 



Of tlie remaiuiug speciiueus of this group the larger number closely corresponded 

 in size to the bullae of Mesoplodon layardi, and were almost identical with them in the 

 configuration of the lobes, in the broad, roughened, inferior surface, and in the curvatures 

 of the inner and outer surfaces, so that I think they should be referred to that animal. 

 I have figured a characteristic one in Plate II. fig. 8. A few specimens in this group were 

 a little smaller than Meso-plodon layardi, but possessed the same general characters of 

 shape, and two specimens were somewhat broader, and more flattened on the inferior 

 surface, than in the immature Falkland Isle layardi. 



The Jifth group consisted of at least twenty-four specimens, which varied in length 

 from 1 inch to 1'7 inch. They were all bilobed, and had the general configuration of the 

 tympanic bulla of the Delphiiiidce. The longest possessed a transverse diameter of 1"1 

 inch, and in its general form resembled the bulla of a Glohiocephalus. It is figured 

 in PI. VIII. fig. 6, by Mr Murray. Others were from animals of the genus Deljihinus, 

 whilst the smallest had the size, and almost exactly the shape, of the common porpoise. 

 A specimen figured in my Plate II. fig. 13, and from another aspect in Mr Murray's 

 Plate VIII. fig. 7, was 1'3 inch long, and "7 inch wide. It was obviously not one of the 

 Dolphins, for it was not bi-lobed posteriorly, whilst its small size precluded it from belong- 

 ing to the Baleen whales. Professor Flower, to whom I showed the specimen, thought from 

 its resemblance in form to the tympanic bulla of the sperm whale (Physeter tiuicroce- 

 phalus), though of course very much smaller, that it might be the bulla of the short-headed 

 sperm whale of the southern seas [Kogia, Gray). There was no tympanic of this whale 

 in the Museum of the College of Surgeons with which to compare it, but in the stores of 

 the British Museum I fortunately met with a specimen marked Kogia macleayii, which was 

 from a young animal, and had unquestionably a considerable resemblance to the deep-sea 

 specimen. The latter was slightly larger, but they were almost identical in shape ; only, the 

 deep-sea specimen was somewhat more roughened on the inferior surface, the anterior or 

 Eustachian orifice was somewhat wider and the internal surface deeper. There can, I 

 think, be little doubt that this bone should be referred to a species of Kogia. Two other 

 specimens also occurred in this series which at the first sight seemed to have some resem- 

 blance to the bulla of Kogia, but on further examination were found to differ in several 

 respects from it. The best preserved was I'l inch long, and is figured in Plate II. fig. 14. 

 It was divided posteriorly into two lobes, but the intermediate depression was very shallow, 

 and was not prolonged as a sharply differentiated groove along the inferior surface. The 

 external posterior lobe was relatively large and boss-like, whilst the internal posterior 

 was much smaller, and almost pointed. It cannot be regarded as one of the Dolphins, 

 Ijut was probably from an animal allied to Kogia, though genericaUy distinct from it. 



In this station forty-two detached petrous bones were also obtained. The longest 

 was 2 inches, which is O'l inch less than the one alreadj^ referred to in the fourth group 

 as still attached to the bulla of the big MesoiDlodon. Several were 1"8 and r9 inch 



