22 CEIACEA. 



foreshadows that of Neobalcena ; the involucrum is thickened and 

 the inferior border angulated. 



M. 3510. Cast of the imperfect right tympanic. The original is 

 from the lied Crag of Woodbridge, Suffolk, and is preserved 

 in the Museum of Practical Geology, Jerinyn Street ; it is 

 described and figured by the present writer in the ' Quart. 

 Journ. Geol. Soc.' vol. xliii. p. 9, pi. ii. figs. 1, la. A 

 specimen in the Brussels Museum (No. 1248) presents 

 somewhat similar characters. 



Made in the Museum, 1886. 



Variety C. 



The tympanic resembles in many respects that of the type 

 variety ; but is much compressed laterally, has no thickening of the 

 involucrum, and the flattening of the anterior surface does not 

 extend much below the superior border of the inner wall ; the 

 inferior border is not angulated. 



46685. The slightly imperfect and partially rolled right tympanic : 

 from the Red Crag of Woodbridge. Noticed by the writer 

 in the ' Quart. Journ. Geol. Soc.' vol. xliii. p. 10. 



Purchased, 1875. 



The inner wall of the tympanic is low, its superior border nearly 

 parallel with the long axis of the bone, the flattening of the 

 anterior surface not extending below that border, and the inferior 

 border of the bone not angulated. 



43399. The imperfect right tympanic ;. from the Red Crag of Wood- 



(Fig.) bridge. This specimen, which has not suffered from 



rolling, is described and figured by the present writer in 



the ' Quart. Journ. Geol. Soc.' vol. xliii. p. 10, pi. ii. 



figs. 2, 2 a. Purchased, 1875. 



M. 3509. Cast of a rather smaller and somewhat rolled imperfect 

 right tympanic. The original was obtained from "Wood- 

 bridge, and is preserved in the Museum of Practical 

 Geology, Jermyn Street ; it agrees very closely in character 

 with the preceding specimen, and is noticed by the writer, 

 loc. cit. Made in theMuseum, 1886. 



28257. An imperfect left tympanic, provisionally referred to this 

 variety ; from Woodbridge. Purchased, 1852. 



