FERESA ATTENUATA 



BY 



Dr. J. E. Gray F. R. S„ F. Z. S. &c. 



(Plate 6 ) 



Mr. Godeffroy has sent to the British Museum the skull of a Dorphin which he had received from 

 the South Seas without any move special habitat. It pröves to be an unrecorded species of the genus 

 Feresa. Tins genus probably belongs to the tribe Lagenorhynehina and is at once known from the other 

 genera of the tribe by having only 10 or 12 teeth on each side of the jaw whereas all the other genera 

 have 20 or 30 smaller and more slender teeth. 



The small number of the teeth and their large size caused the skull on which the genus was 

 established to be referred to the genus Orca, and Mr. Flower considered that the specimen on which the species 

 was established was the young of a larger species of that genus, but the solidity of the skull and the more 

 carefiü examination of its characters shows that it is the skull of an adult animal and the flattened or 

 slightly concave upper surface of the beak that it belongs most probably to this tribe, leaving it however 

 be determined when the animal and especially the form of the flappers or pectoral fins are known whether 

 it is related to Lagenorhynclms or Orca. 



Feresa attenuata is known from Feresa intermedia by the shape of the beak and by the teeth being 

 more slender and farther apart. 



The characters of the two species may be thus stated: 

 Feresa attenuata. 



The beak gradually narrowed towards the front and rather acute in front. Teeth rather slender 

 and far apart. The three teeth in the middle of the sides of the jaws occupy lVc inch of the margin, 

 the two or three hinder teeth on each side of the upper jaw are much smaller and more slender than the 

 other s. The total length of the skull from the condyle to the front of the beak is 13 Va inches, the width 

 of the skull over the front of the eyebrows is 8 inches, the width of the beak at front of notch 4Va inches, 

 and at "k its length 2-U inches, length of tooth-line 5 inches. 



Hab. South Seas. 



Feresa intermedia, Gray, Sappl. Cat. Seals and Whales in British Museum, p. 78. 

 Orca intermedia, Gray, Zoology Erebus and Terror p. 34- t. 8 (skull). 

 Beak of the skull dilated and rounded in front, the teeth large and thick, the three on the sides 

 of the jaw occupying P/12 inch the upper hinder one on each side being smaller and more slender. 

 Hab. unknown. 



This was the last paper written by J0I111 Edward Gray for publication. When the 

 proof arrived in London, he had gone to bis rest, March 7. 1875. A. Gr. 



184 



