54 CETACEA. 



Genus PHYSETERULA, Yan Beneden\ 



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

 the symphysis is only one third that of the mandible. 



Physeterula dubusi. Van Beneden^ 



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

 individuals of Physeter macrocejjJialus, but with relatively longer and 

 more slender teeth. 



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



49966. One half of a longitudinally bisected tooth, provisionally 

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

 bridge, Suffolk. This specimen apparently agrees with 

 the teeth of the type mandible figured by Yan Beneden 

 in the ' Bull. Ac. R. 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^ 



Syn. Dinoziphius, Van Beneden *. 



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^ 

 Syn. Dinoziphius ramdoncld, Van Beneden 6. 

 This is the typo and only species ; teeth from the lied Crag in the 



1 Bull. Ac. E. Belg. 86r. 2, vol. xliv. p. 8.51 (1877). ^ j^^^ ^^^ 



3 Ibid. vol. xxiv. p. 572 (18G7). 



4 Quoted by Gervais in the ' Ost6ograpbie des Oetaces,' p. 344 (1867-79). 

 The specific name is misspelt. 



^ Log. cit. ^ hoc. cit. 



