250 DELPniNIDJE. 



Var. In the Museum of the Bristol Institution there is an imper- 

 fect skull, apparently of this species, which differs in the nose being 

 about three-quarters of an inch shorter, and rather narrower. It has 

 36 teeth in the upper jaw. 



in. lin. 



Skull : Length of nose 8 7 



Width at notch 3 8 



"Width at middle of nose 2 



A lower jaw is fitted to it, which has no teeth and a short gonyx, 

 but it is doubtful if it belongs to the same animal ; its length is 12| 

 inches, symphysis Ig inch. 



A second skull in the same collection is very similar, and has 

 M teeth. 



in. lin. 



Skull : Length, entire 15 



Length of nose 9 



Width at notch 3 4 



Width at middle of nose 110 



This skull only diflPers from the former in the lower jaw being 

 slenderer and united by a longer symphysis in front. Lower jaw 

 1 2^ inches long ; symphysis 2 inches. 



These are probably indications of two other species. The hinder 

 part of the skull of the latter is also rather more convex than the 

 same part in D. Plierma. 



In the description of this species in the * Zoology of the Erebus and 

 Terror,' D. Metis is mentioned in three places instead of D. Dons. 



13. Delphinus Styx. The Styx. 



Skull roundish, flattened behind ; nose depressed, convex in the 

 middle, shelving on each side, longer than the head, five-ninths the 

 entire length, nearly twice and a half as long as the width at the 

 notch ; the triangular impression just to the line of the hindermost 

 teeth. Teeth ^, slender, subcyHndrical, acute, about five in an inch ; 

 palate nearly flat ; lower jaw rather produced and roiinded in front. 



Delphinus Styx, Gray, Zool. E. 8f T. 40. t. 21 (skuU) ; Cut. Cetac. 

 B.M. 1850, 117. 



Inhab. W. Africa {Capt. W. T. W. Oiven, B.N.). 



Skull in Mus. United Service Institution : — . ,. 



Length, entire 18 



Length of nose 10 3 



Length of lower jaw 14 9 



Width at the notch 4 6 



Width at the orbit 8 6 



Teeth || 



This species is very like D. Euphrosyne, but is somewhat smaller 

 and the beak rather shorter ; it may prove to be only a variety. 



