54 CETACEA. 



Genus PHYSETERULA, Van Bcneden 1 . 

 This genus appears closely allied to Physeter, but the length of 

 the symphysis is only one third that of the mandible. 



This is the type species, and is about one third the size of medium 

 individuals of Physeter macrocephalus, but with relatively longer and 

 more slender teeth. 



Hob. Europe (Belgium and [?] England). 



49966. One half of a longitudinally bisected tooth, provisionally 

 referred to this species ; from the Red Crag of Wood- 

 bridge, Suffolk. This specimen apparently agrees with 

 the teeth of the type mandible figured by Yan Beneden 

 in the ' Bull. Ac. K. Belg.' ser. 2, vol. xliv. pi. facing 

 p. 856 ; it is noticed by the writer in the ' Quart. Journ. 

 Geol. Soc.' vol. xliii. p. 14, under the name of Homocetus 

 villersi, to which form the type mandible was referred by 

 Du Bus. Purchased, 1879. 



Genus .EUCETUS, Du Bus 3 . 

 Syn. Dinoziphius, Van Beneden 4 . 



The teeth of this genus closely resemble those of Physeter, being 

 only distinguished by their subcircular cross section and the small 

 size of the inferior aperture of the pulp-cavity. Apart from the 

 question of enamel, the teeth differ from the type of Balcenodon by 

 the fusiform dentine core, and the frequent presence of an axis of 

 osteodentine of a nodular structure, and lighter in colour than the 

 dentine. The periotic provisionally assigned to the genus is nearer 

 to that of Hyperoodon than to that of Physeter ; and this reference, 

 if correct, would indicate the right of the present genus to stand, 

 unless it be founded on worn teeth of Scaldicetus. 



Eucetus amblyodon, Du Bus 5 . 

 Syn. Dinoziphius ramdoncki, Van Beneden 6. 

 This is the type and only species ; teeth from the Red Crag in the 



1 Bull. Ac. R. Belg. ser. 2, vol. xliv. p. 851 (1877). 2 Loc. tit. 



s Ibid. vol. xxiv. p. 672 (1867). 



4 Quoted by Gervais in the ' Osteographie des C6tac6s,' p. 344 (18(57-79). 

 The specific name is misspelt. 



6 Loc. tit. e Loc. tit. 



