8 ME. R. LYDEKKER ON THE CETACEA OP THE SUFFOLK CRAG. 



As the result of these extensive comparisons, I have been able not 

 only to add a considerable number of species to the British fauna, but 

 to make several important emendations in regard to nomenclature, 

 and also as to the affinities of certain forms which have hitherto been 

 but very improperly known ; and I have accordingly thought it 

 advisable (with the permission of the Director and the Keeper of the 

 Geological Department of the British Museum) to bring these results 

 in a collective form under the Society's notice. I think I may be 

 congratulated that I have not found it necessary to make any new 

 species. 



Before proceeding to the descriptive part of the paper it may be 

 advisable to state that my own observations fully confirm the con- 

 clusions arrived at by Prof. Lankester, as to the essentially Diestian 

 affinities of the English Crag Cetacea. In the Coralline Crag the 

 specimens are usually met with in an unrolled condition ; and 

 although the remains found in the bone-bed at the base of the Bed 

 Crag are much rolled and water-worn, yet specimens belonging to 

 the same species are found occasionally in the upper portions of 

 that deposit, in a more or less uninjured condition, which clearly 

 proves that such species were inhabitants of the Pliocene sea during 

 the deposition of the Bed Crag. With these introductory remarks 

 the consideration of the fossils themselves may be undertaken *. 



Balcenidce. — Commencing with the Balaenine section of the family, 

 it appears to me to be advisable to include in the genus Bahama 

 both Balcenotus and Balcenula of Yan Beneden, as these forms seem 

 to be nothing more than primitive Bight Whales, in which the 

 anchylosis of the cervical vertebras had not attained the full develop- 

 ment characteristic of the existing forms. Of the four tympanies 

 described by Sir B. Owen in the fourth volume of the Society's 

 ' Proceedings,' and in the ' British Possil Mammals and Birds,' under 

 this generic designation, the only one that really belongs to Balcena 

 is B. affinis. The type-tympanic is not of very large size, but there 

 are specimens in the British Museum {e.g. No. 46681) corresponding 

 in form which indicate a species fully as large as, and apparently 

 closely allied to, the Greenland Whale ; there are similar specimens 

 in the Brussels Museum which have been referred to B. primigenia, 

 Yan Beneden (a reference which, if correct, would indicate that the 

 latter name is a synonym of B. affinis), but which differ from typical 

 tympanies of that species. The tympanic of B. affinis is characterized 

 by its elongated shape and flat anterior surface, its nearly straight 

 inferior border, which is approximately parallel with the superior 

 border of the inner wall, the height of the inner wall at the Eusta- 

 chian part of the aperture, the produced antero-inferior angle, and 

 the slight thickening of the involucrum f . 



In addition to this type of tympanic the Bed Crag contains nu- 

 merous examples of the tympanies of other large Whales, which in 

 their convex inferior border, absence of a produced antero-inferior 



* As the references to the nomenclature will be given in the British Museum 

 Catalogue, it will be unnecessary to quote them in this paper, 

 t The reflected superior portion of the inner wall. 



