322 THE BOOK OF THE ANIMAL KINGDOM 



oceans, the species under review has not at present been found 

 there. 



LAYARD'S WHALE. This Whale is a typical southerner, being 

 found in the seas of the Southern Hemisphere, and is characterized 

 by the possession of two large teeth which "become lengthened by 

 continuous growth of the fangs into long curved tusks. These arch 

 over the upper jaw or beak, and crossing one another above it at 

 their tips, form a ring round it, and lock the lower jaw, so that the 

 animal can only open its mouth for a very short distance indeed. 

 The tusks are seen always to be worn away in front by the grating 

 of the confined upper jaw against them. How the animal manages 

 to feed itself under these conditions is a mystery." 



It is stated by competent authorities that these remarkable teeth 

 hamper rather than help Layard's Whale, and afford an instance of 

 one of those curious developments in an animal which it is difficult 

 to understand the meaning of. This is a very rare species, but is 

 worth mention by reason of the growth of the teeth just alluded 

 to. 



ARMTJX'S WHALE. Before coming to the Porpoises and Dolphins 

 brief reference may be made to Armux's Whale, which is an inhabit- 

 ant of the seas round New Zealand. It is a larger beast than the 

 last mentioned, attaining a length of some thirty feet, and is 

 distinguished from its relatives by having two pairs of teeth which 

 are situated close to the front part of the jaw. 



FRESH-WATER DOLPHINS. There are three species of these 

 animals, and they are closely related to the true Dolphin to be con- 

 sidered towards the end of this section. They are small beasts, and 

 whilst two are restricted to fresh water, the third is a tenant of estu- 

 aries. The best known of the three species is the Susu, or Gangetic 

 Dolphin, which inhabits the Indus, Ganges, and Bramaputra Rivers 

 of India. It attains a length of some seven or eight feet, perhaps 

 more, and the female is larger than her mate. Curious to relate, 

 this Dolphin is quite blind, and it has been suggested that in view 

 of the turbid nature of the waters it frequents sight would be of 

 little, if any, use to it. It is not particularly gregarious, although, on 

 occasions, several individuals may be seen together, and those who 

 are acquainted with the habits of these interesting creatures are able 

 to locate them by means of the blowing noise they make when 

 engaged in rising to breathe. This detection, however, is only 

 possible when the water frequented is comparatively quiet in the cold 



