76 MAMMALIA. 



JVlr. Lydekker (Quart. Journ. Geoi. Soc, Vol. XLIIL, p. 16, 

 1887) in his more recent revision of the Cnig Cetrtcea, has come 

 to the conclusion that the two forins of teeth described by Prof. 

 Lankester really belong to one species, he says : " The next form 

 for consideration is that to which Prof. Lankester applied the 

 name Delphinus uiicidens (the generic term being used in the 

 Linnean sense), with which D. orcoides of the same author 

 may be united, since the larger teeth to which the latter name 

 W.1S applied are merely the hinder ones of the same species. 

 Some contusion occurs in the description of the larger teeth, 

 since they are stated to agree in size with those of Pseudorca 

 and Orca, whereas they really correspond in this and other 

 respects with those of Glohicephalus, to which genus they may 

 be referred. The evidence for this reference does not, however, 

 depend solely upon the teeth, since there is in the British 

 Museum a very beautiful associated left periotic and tympanic 

 from the Coralline Crag, (the former bone being represented in 

 [Quart. Journ. Geol. Soc] Plate II., fig. 11) which agree pre- 

 cisely in size with the corresponding bones of G. melas, and only 

 present slight structural differences of specific value." 



The periotic bones figured by Profs. Van Beneden and Ger- 

 vais (Ost^ographie de Cetac^s, Plate Ix, figs. 1 and 8), from Italy 

 and the Sufiblk Crag, seem to be specifically identical with that 

 figured by Mr. Lydekker, and there is another periotic from the 

 Eed Crag Nodule-bed of Woodbridge, referable to the same 

 species, in the Museum of Practical Geology (Plate VIII, fig. 8). 



The periotic bone figured by Profi Lankester {loc. cit, Plate viii, 

 fig. 2, 3) as D. uncidens has not the same form as that which Mr. 

 Lydekker (loc. cit, Plate ii., fig. 1 1) now refers to G. uncidens. 

 A lumbar vertebra from the Red Crag, in the British Museum 

 (No. 28,271) and possibly some vertebra from the Antwerp Crag 

 in the Brussels Museum, are referred by the last-named writer to 

 the present species. 



Mr. E. Cavell, of Saxmundham, has a tooth agreeing with this 

 species, from the Norwich Crag of Thorpe. Glohicephalus uncidens 

 has thus been recognised in the true Coralhne Crag, the Red Crag 

 Nodule-bed, and in the Norwich Crags ; possibly also In the Ant- 

 werp Crag. 



Genus MONODON, Linneeus. 



MONODON MONOCEKOS, LINNMUS. 



{Narwhal.) 



(Vert. Forest Bed, Plate IX., Fig. 2.) 



The occurrence of the Narwhal in the Cromer Forest-bed 

 has long been known, and references will be found in the Survey 



