76 MAMMALIA. 



DELPHINIDJE. 



Genus ORCA, Gray. 



CITONIENSIS, CAPELLINl. 

 PLATE VII., FIG. 4, and PLATE VI LL, FIG. 5. 



A large portion of a Delphinoid skeleton from Pliocene beds at 

 Cetona have been described by Prof. G. Capellini (Mem. Ac. 

 Sci. Inst. Bologna, Ser. 4, Vol. IV., p. 665, 1883) and named 

 Orca citoniensis, and Mr. Lydekker (Quart. Journ. Geol. Soc,, 

 Vol. XLIII.,p. 15, 1887) refers to the same species two specimens 

 from the Red Crag Nodule-bed of Suffolk. The first of these is a 

 right periotic bone in the Museum of Practical Geology which 

 while agreeing in form with that of Orca gladiator is much 

 smaller. The second specimen is a tooth in the Ipswich Museum, 

 which probably belongs to the same form as the periotic bone, and 

 agrees with the teeth of Orca citoniensis. 



ORCA GLADIATOR, GRAY. 

 (Killer or Grampus.) 



While this Memoir is passing through the press, Mr. Savin has 

 sent me some specimens recently obtained from the Forest -bed, 

 two of which are referable to the Killer ( Orca gladiator). One 

 of these, from East Runton, is the centrum of a dorsal vertebra, 

 with the bases of the transverse processes preserved, which agrees 

 in size and proportions with one of the hinder dorsal vertebrae 

 of the Orca gladiator preserved in the Royal College of Sur- 

 geons. 



The length of the centrum is 113 mm. (nearly 4J inches), the 

 width of the posterior face 113 mm. and its height 103 mm. 

 The anterior face has the same height as the posterior, but its 

 width is less, 106 mm. The under surface and sides of the 

 centrum are concave from before backwards, but rounded from 

 side to side. The upper, neural, surface is wide and flattened, 

 with two large foramina, one on each side of the middle line, a 

 little towards the front. The terminal faces are nearly flat and 

 the epiphyses are firmly ankylosed. 



The second specimen is a tooth from the Forest-bed of Pake- 

 field, it measures 76 mm. in length and 65 mm. in circumference 

 at its widest part. The enamel crown, which is somewhat broken, 

 is curved and nearly round, while the rest of the tooth is inflated, 

 but somewhat flattened, with a depression along one side, and is 

 marked by irregular concentric rings. This tooth agrees pre- 

 cisely with one of the smaller teeth of the Killer. Jn size, but 



