322 WHALES AND DOLPHINS 



The young are born about the middle of the summer. 

 Stranded specimens include several very small newly-born 

 animals about 4 feet in length, and all reported after the middle 

 of the year. 



Like L. acutus this species is gregarious in habit. Beddard 

 states — " It occurs in vast herds of as many as 1500 individuals 

 on the coast of Norway ; it is then in pursuit of herrings." 

 Other common fishes such as whiting are included in its diet. 



Lagenorhynchus cruciger. Fig. 87. 



In general form L. cruciger is like the White-sided Dolphin, 

 but is rather smaller in size, 5 to 6 feet being given as the adult 

 length. It is a more conspicuously marked species than either 

 of those described above, and is South Pacific in range. 



The beak is short and indistinctly marked off from the fore- 

 head ; the dorsal fin is large, and with pronounced concavity 

 of hinder margin. The colour distinguishes this species. The 

 snout and lower jaw are black and this colour extends along 

 the back to the tail flukes. On the sides a second band of 

 pigment, originating at the eye and stretching to the tail 

 flukes, widens out just behind the flipper so that its upper 

 edge merges with the black of the back. It then narrows near 

 the level of the vent and again widens out before reaching the 

 tail flukes, in front of which it merges with the black of the 

 back and ventrally with the corresponding band on the other 

 side of the body. Occasionally the lateral black area does not 

 make contact with the dorsal one behind the flipper, so that 

 an uneven white band extends from above the eye to the tail. 



Teeth number 28 pairs in upper and lower jaws. 



Nearly allied to if specifically distinguishable from this 

 species is Wilson's Hour-glass Dolphin (L. wilsoni), which 

 differs in having a more pronounced snout, and in having the 

 lower black band on the one side meeting on the under surface 

 with that of the other side of the body in the region of 

 flipper insertion. It is also believed to be somewhat larger in 

 size. This form was frequently seen just north of the pack-ice 

 during both the " Discovery " 1902 Expedition and the 

 " Terra Nova " Expedition to the Antarctic. No specimens 

 have yet been caught. 



