NOTES AND QUERIES. 189 



over a rocky bottom with great velocity." The officers and crew 

 immediately rushed on deck, thinking a boiler had burst, or that 

 the ship had gone aground, but the boilers were all right, and the 

 lead failed to find bottom at 100 fathoms. The weather was 

 foggy, with slight rain and wind from E.S.E. ; no upheaval of 

 the water was noticed, the sea being unusually calm. About two 

 hours later, a second but much lighter shock was experienced, 

 which, however, only caused the vessel to tremble. 



NOTES AND QUERIES. 



MAMMALIA. 



Change of Habits in the Brown Rat.— The way in which animals 

 change their habits and mode of life in adapting themselves to new or 

 altered conditions of existence is very remarkable. In some cases doubtless 

 the change is so gradual that it is not detected for a long time, but in others 

 a divergence of habit under exceptional circumstances is so marked that it 

 at once strikes the observer as noteworthy. Some years ago the Rev. J. S. 

 Whitmee, then resident in the Samoan Islands, noticed a remarkable change 

 of habits in that curious bird the so-called "Little Dodo," Didunculus strigi- 

 rostris, which, from being almost entirely terrestrial in its habits, and 

 breeding also on the ground, became gradually arboreal, roosting and nesting 

 iu trees, to escape the destruction which threatened it from attacks by cats, 

 dogs, rats, and pigs, which had been introduced by the colonists [cf. Proc. Zool. 

 Soc. 1875, p. 495). The Rat itself, so active a destroyer of life, has likewise 

 had to alter its habits continually in its struggle for existence under adverse 

 conditions in New Zealand. Capt. Johnstone, of Te Haroto, Raglan, New 

 Zealand, referring to Mus decumanus, in a letter to Capt. Hutton, subse 

 quently communicated to the Auckland Institute (Proc. N. Z. Inst. 1870, 

 p. 47), writes as follows: — "At this season of the year [June] there is a 

 sort of annual migration of Rats, where there are uncultivated lands in the 

 neighbourhood of houses. This year the migration is ■ excessive, both 

 iu the country and in the village of Raglan. The habits of the Rat 

 have greatly changed since its introduction. It is amphibious. At low 

 water they go to eat shell-fish on a rock near here, and when the tide rises 

 swim back to the land. They have almost extirpated the delicious little 

 crayfish (Paranephrops), which twen'y years ago were, as I well remember, 

 plentiful in my creek. Even the fresh-water mussels (Unio) are not safe 

 from them, as they dive for them and open them on the bank. The climate 

 is wet and the ground hard, so instead of burrows they make nests iu trees 



