. CETACEA. 61 



MEGAPTERA (BURTINOPSIS) MINUTA, v. BESEDEN. 

 PLATE VI., FIGS. 7</, b. 



Megaptera minuta, was described by Prof. Van Beneden (Bull. 

 Ac. Roy. Belg., Ser. 2, Vol. L., p. 17, 1880, and Ann. Mus. 

 Roy. Hist. Nat. Belg., Vol. VII, Part 3, p. 80, 1882) from specimens 

 found in the Antwerp Crag. This, which is the smallest of the 

 three species of Megaptera found in the Crag, is represented in 

 the true Coralline Crag of Suffolk by a nearly perfect tympanic 

 bone in the Ipswich Museum, and in the Nodule-bed of the Red 

 Crag of Foxhall by a rolled specimen in the Museum of Practical 

 Geology. 



Mr. Lydekker (Quart. Journ. Geol. Soc., Vol. XLIIL, p. 11, 

 1887) says : " Except by its smaller size, the English specimen 

 [from Coralline Crag] can scarcely be distinguished from the 

 tympanics of the existing M. boops." 



Genus BAUENOPTERA, Lacepede. 



BAL^ENOPTERA DEFINITA, OWEN. 



PLATE VI., FIGS. 8a, b. 



This is one of the four species founded by Sir R. Owen (Proc. 

 Geol. Soc., Vol. IV., p. 283, 1843 ; Quart. Journ. Geol. Soc., 

 Vol. L, p. 39, 1845, and Brit. Foss. Mamm.,.p. 531, 1846) for Crag 

 tympanic bones. The original specimens being imperfect it has 

 always been troublesome to know what should be referred to these 

 species, but with regard to the one under consideration, Mr. 

 Lydekker (Quart. Journ. Geol. Soc., Vol. XLIIL, p. 11, 1887) 

 says there is a fairly perfect tympanic in the Ipswich Museum 

 which <f agrees exactly with the imperfect type tympanic (of which 

 a cast is preserved in the Museum of the College of Surgeons) ; 

 and as it differs from the corresponding bone of B. Goropi by its 

 larger size, its greater inflection, greater height of the inner 

 wall, smaller depth of the Eustachian notch, sharper posterior angle, 

 and more gibbous involucrum, there is little doubt of its specific 

 distinctness, and every probability of its being identical with 

 the so-called B. Sibbaldina, V. Ben. [Ann. Mus. Roy. Hist. 

 Nat. Belg., Vol. VII., Part 3, p. 63, 1880] of which the tympanic 

 has been hitherto unknown. This is confirmed by a very fine 

 late cervical vertebra from the Red Crag in the Ipswich 

 Museum, which corresponds exactly with the type specimen of 

 the latter form in the Brussels Museum." 



If Mr. Lydekker is correct in referring B. sibbaldina to this 

 species, then B. definita, Owen, occurs in the Nodule-bed of the 

 Red Crag of Suffolk and in the Antwerp Crag. 



