3 3 4 THE IND0-PAC1F1C AND ITS SHORES 



Although brief reference to the albatroses on Laysan Island has 

 Albatroses. 



been already made in the chapter on the animals of the Antarctic, 



it may be mentioned here that these birds make their appearance on that island 

 several months after the arrival of the blue petrels, the usual date being the last 

 week in October. When all these great birds have taken up their quarters in their 

 breeding-places on Laysan and other lonely Pacific islands they specially affect, their 

 numbers are so great that scarcely a spot is left unoccupied, and it not infrequently 

 happens that some members of the colony have to seek accommodation on other 

 resorts. The last birds to arrive naturally get the worst breeding-stations, and 

 in many cases are compelled to establish themselves on the shores of lagoons 

 covered during dry weather with a thin white crust of salt, which after a rain be- 

 comes mixed up with the underlying soil so as to form a kind of alkaline mud of a 

 highly corrosive nature. In such situations the mortality among the young birds 

 is very large, hundreds of their carcases covering the ground. Even, however, in 

 more favourable localities numbers of young perish, owing to their parents being- 

 driven far away by storms or prevented from returning with food at the proper 

 time. Young albatroses present at all times a somewhat comical appearance, and 

 especially so when their downy coats are disarranged by the wind. Although to 

 the human eye the young are so like one another as to be absolutely indistinguish- 

 able, the female parents never display the slightest difficulty in recognising their 

 own offspring among the thousands which crowd the ground, even should they 

 have strayed some distance from the spot where they were left in the morning. 



So soon as the young are fairly developed, they begin to half run and half fly 

 across the sand, daily getting a little nearer to the sea, even those that cannot see 

 it, taking the nearest line to the shore. Once they have reached the water, nothing 

 will keep them back, and in many cases they pay with their lives for their temerity, 

 especially on steep shores washed by heavy seas. The species breeding on Laysan 

 Island are Diomedia im/mntabilis and D. sinensis, the habits of which appear to 

 be generally similar to those of the wandering albatros. 



Among the reptiles of the Indo-Pacific are the four well-defined 



Turtles 



species of marine turtles, none of them being, however, restricted to 

 this area. All of them are characterised by their paddle-like limbs, but the leathery 

 turtle, or luth (Dermochelys, or Dermatochelys, coriacea, also known as Sphargis 

 coriacea), differs from the rest, and, indeed, from all other living members of the 

 chelonian order by the peculiar structure of the shell. In ordinary turtles, as in 

 land and fresh-water tortoises, the upper shell is firmly soldered to the vertebrae of 

 the back and ribs, and consists of a number of bony plates varying in size and shape 

 in different parts, but with the large lateral ones which overlie the ribs forming 

 symmetrical pairs, and the whole being covered by horny plates, which are like- 

 wise arranged symmetrically, although they do not correspond in shape and size to 

 the underlying bones. In the luth, on the other hand, the upper shell is quite 

 distinct from the vertebrae and ribs, from which it can be lifted as a separate 

 vaulted shield, composed of a number of small, mosaic-like pieces of bone not 

 arranged in symmetrical lateral pairs ; although there are five longitudinal ridges, 

 on the back, to the presence of which the species owes its name of luth, since they 

 are supposed to present a resemblance to an ancient lyre. The whole is invested 



