W RALES AND DOLPHINS 313 



tusks were 14 inches in length, 2J inches wide at the jaw, If inches at the 

 summit beneath the conical real tooth, and from f to h inch in thickness. The 

 nippers measured 22 inches in length; the back-fin, which is situated far back, 

 was 13 inches wide and 11 inches high; the tail, 4 feet 6 inches across at its 

 extreme width ; and the interval from the point of the beak to the eye 38 inches, 

 and to the end of the jaw 4 feet. The exposed portion of the teeth was 11 inches 

 long and 2h inches wide at the base, becoming slightly narrower towards the tip, 

 which carried the conical real tooth at the front of its summit; this tooth beino- 

 enamelled and sharply pointed. 



Still more rare is the species known as Mesoplodon densirostris, which 

 has also been taken in South African waters, and has teeth of a more normal type. 

 A fourth is Gray's beaked whale (M. [Dioplodon] grayi), originally described 

 from New Zealand but subsequently recorded from South Africa, where a speci- 

 men was stranded at Port Elizabeth in 1910. That specimen measured 15| feet in 

 length, from the tip of the muzzle to the end of the tail, or flukes. In colour it 

 was jet-black all over; and the flukes was remarkable on account of the posterior 

 border being convex, instead of deeply scooped out (emarginate), as in ordinary 

 cetaceans. A feature similar to that found in the tail of the Port Elizabeth speci- 

 men is stated to occur in a beaked whale from Annisquam, Massachusetts, which 

 is referred to the above-mentioned M. densirostris, a near relative of M. grayi 

 (with which M. australis is identical), and it therefore seems that the former like- 

 wise belongs to the subgenus Dioplodon. 



An equally rare representative of this group inhabiting southern waters is the 

 species named Arnux's beaked whale (Berardius arnuxi), the sole member of its 

 genus, and remarkable for the expanded triangular form of the single pair of large 

 lower teeth, which are situated near the extremity of the jaw, instead of in the 

 middle, as in Layard's beaked whale. Arnux's whale, which is black above and 

 grey beneath, grows to nearly 30 feet in length, and has been taken off the coasts 

 of New Zealand and also in the estuary of the Rio de la Plata. In connection 

 with the rarity of the beaked whales it may be mentioned that an American 

 naturalist was unable to discover records of more than about one hundred specimens 

 in collections belonging to the aforesaid genera and to the northern Ziphius, the 

 typical representative of the group ; more than half of these belonging to the genus 

 Mesoplodon, Berardius being known only by about fourteen examples. An im- 

 portant addition to our knowledge of the group was the discovery of representatives 

 of all three genera at Bering Island in the western North Pacific, two of these 

 being regarded as distinct species, which were subsequently ascertained to range 

 into the eastern North Pacific. 



From the seas around the Cape of Good Hope has been obtained a small 

 dolphin belonging to the family Delphinidai, characterised by the bold contrast of 

 black and white in its colouring, and thus recalling the much larger grampus, or 

 killer. This dolphin, which represents a genus by itself, is known as Cephalo- 

 rhynchus heavisidei. During the Discovery expedition an apparently undescribed 

 dolphin, remarkable for its peculiar type of colouring, was observed in the 

 neighbourhood of the Antarctic ice. It attains an apparent length of from 

 8 to 10 feet, and may be described as a chocolate-brown dolphin, with two large 



