18 



MK. E. LYDEKKER ON THE CETACEA. OE THE SUFFOLK CEAG. 



EXPLANATION OF PLATE II. 



Figs. 1, la. Balcena primigenia, Van Beneden,. var. B. The imperfect right 

 tympanic ; from the Bed Crag. Museum of Practical Geology. 



2, 2a. Balcsna primigenia, Van Beneden, var. D. The imperfect right 

 tympanic ; from the Bed Crag. British Museum (No. 43399). 



3,3a. Balcenoptera definita ( Owen). The imperfect left tympanic ; from 

 the Bed Crag. Ipswich Museum. 



4. 4a. Megaptera affinis (Van Beneden). The imperfect immature right 



tympanic ; from the Coralline Crag. Museum of Practical Geology. 



5. 5a. Megaptera minuta (Van Beneden). The imperfect left tympanic; 



from the Coralline Crag. Ipswich Museum. 



6. Hyperoodon, sp. The right periotic ; from the Red Crag. Ipswich 



Museum. 



7. Choneziphius planirostris (Cuv.). The left periotic ; from the Bed Crag. 



Museum of Practical Geology. 



8. Mesoplodon (? longirostris [Cuv.]). The left periotic; from the Bed 



Crag. Museum of Practical Geology. 



9. Orca citoniensis, Capellini. The right periotic ; from the Bed Crag. 



Museum of Practical Geology. 



10. Ditto. A tooth ; from the Bed Crag. Ipswich Museum. 



11. Globicephalus uncidens (Lank.). The left periotic ; from the Coralline 



Crag. British Museum (No. 36657). 



Figs. 1, 2, 3, one half, figs. 4, 5, two thirds, figs. 6, 7, 8, 9, 10, 11, nat. size. 

 All the tympanies are viewed from the inner and inferior, and the periotics from 

 the tympanic aspect, a, anterior articular facet for tympanic ; b, posterior 

 articular ridge for tympanic ; c, accessory ossicle, or hollow for the same ; 

 d, e, f mark the homology of the ridges and hollows in the different bones ; 

 a, the capsule containing the semicircular canals. 



Discussion. 



Mr. Newton regretted the absence of Prof. Flower. He had 

 tried to determine some of the specimens himself, and recognized 

 how very difficult a task it was. He complimented Mr. Lydekker 

 on his work. With regard to the fossil Physeteroid teeth, he was 

 under the impression that there was more cement in them than in 

 recent teeth. 



Mr. Lidekeee, in reply, said his remark as to the absence of 

 cement only referred to the type specimen of Balcenodon. 



