NAUTILUS 



NAVAL RESERVE 



409 



lives, are filled with gas apparently a mixture of 

 oxygen and nitrogen somewhat different from air. 

 The outside of the shell is covered with a thin 



Fig. 1. Pearly Nautilus (after Owen). Contracted spirit 

 specimen, with the shell in section : 



o, dorsal ' hood ' portion of the ' foot ; ' b, a portion of the 

 mantle reflected on the shell ; c. tentacles ; d, eye ; e, ventral 

 ide of visceral hump; /, funnel ; y, a partition between two 

 chambera ; 8, siphuucle or tube traversing the cliainbera. 



organic layer, beneath which there is a porcelain- 

 like stratum with liand.s of colour, while inter- 

 nally the lime has the usual mother-of-pearl struc- 

 ture, the lustre of which, often artificially exposed 

 by the use of acids, ha- earned for the animal its 

 common name of Pearly Nautilus. 



Though the Nautilus SIM-IMS ti have been known 

 to Aristotle, and though the shells have always 

 been familiar, our knowledge of the animal itself 

 is almost wholly due to the investigations of Owen, 

 and to some interesting observations ( 1705) by the 

 Dutch naturalist Kiim|>lmis. The rarity of speci- 

 mens, so evident from the fact that only one was 

 collected on the Challenger expedition, is mainly 

 due to its hahitnt in somewhat deep water. But 

 it mii-t also be noted that the natives of Fiji, the 

 New Hebrides, the Moluccan Islands, &c. catch 

 the animal in lobster -puts and eat it with relish. 

 The Nautilus probably cree| or gently swims along 

 the sea- bottom, feeding on crustaceans and the 

 like ; but it is also seen floating on the surface, 

 probably washed up by storms and injured by the 

 waves. The species best known is Nautilus pom- 

 jrilius, but there are probably four or five others, 

 while the fossil relatives are reckoned in hundreds. 



The I'n/if r \iin/iin.i ( Ai;/,,nnla) is a very 

 different animal, like an octopus except that the 



Fig. 2. Female Paper Nautilus, showing the two 

 modified arms which make and embrace the shell. 



female bears a beautiful, translucent, ribbed shell 

 in which the eggs are sheltered. But this shell is 



not in any way comparable to that of the Nautilus 

 or of other molluscs ; it is a cradle, not a house ; 

 it is secreted and embraced by two broadened 

 dorsal ' arms,' not by the mantle ; it is nnchambered 

 and peculiar to the females. The Argonaut was 

 credited by Aristotle with the power of lifting its 

 broad arms, and of thus sailing before the wind, 

 but there is no truth in this fancy often reiterated 

 by poets and naturalists. For the Argonaut squirts 

 water from its funnel and swims backwards like 

 aiw other cuttle-fish, or else creeps along the 

 bottom. At the breeding season it is a pelagic 

 surface swimmer in tropical seas, at other times it 

 seeks the depths. The male measures little more 

 than an incn in length, only about a tenth of the 

 size of his mate, and he is also notable for the 

 modification of one of the arms into a detachable 

 sac of spermatozoa, formerly mistaken for a para- 

 sitic worm. Some half-dozen living species are 

 recorded. See CEPHALOPODA, CUTTLE-FISH. 



NailVOO' (from Heb. ndrcir, 'to be beautiful'), 

 a village of Illinois, on the east bank of the Missis- 

 sippi River, 14 miles above Keoknk. It was built 

 by the Mormons (q.v.) in 1840, and in afew months 

 contained a population of 15,000. Its principal 

 feature was a great temple of white limestone 

 ( 1841-45) ; but it had also mills and factories, and 

 the beginnings of a university, and was for a few 

 years a prosperous and happy town. After the 

 expulsion of the Mormons in 1846, the temple was 

 half destroyed by fire in 1848, and further ruined 

 by a tornado in 1850. The town was for a time 

 occupied by French Socialists, and has now only 

 13-21 inhabitants. The Nawvoo Legion was a 

 Mormon military organisation, embracing all the 

 males l>etween the ages of sixteen and fifty, founded 

 herein 1840, and reorganised in Utah in 1857. In 

 1870, when it mustered for the last time, it num- 

 bered about 13,000 men. . 



Naval Cadets. See CADET, MIDSHIPMAN. 



Naval Reserve, KOYAL, is a sort of militia 

 auxiliary to the royal navy. It is a force held in 

 high estem by naval men, and is considered an 

 extremely valuable reserve of trained men ready 

 to man the fleet in case of emergency. The 

 act under which the force was instituted in 

 1859 authorises the engagement of 30,000 men, 

 each for a period of five years, and provides that 

 each shall be trained for twenty-eight days in every 

 year to the use of arms anJ in naval gunnery, 

 either in ships of the navy or on shore. In case 

 of national emergency, these men can, by royal 

 proclamation, be called out for service in the 

 navy in any part of the world, for periods not 

 exceeding five years. While training and while 

 called out for actual service, the men receive the 

 same wages as corresponding ratings in the royal 

 navy ; and in addition they receive a retaining 

 fee for every year of training completed, the 

 amount of which is regulated according to the 

 class of the reserve in which they are enrolled ; 

 this is 8 a year for men in the fust class, and 

 2, 10s. with a suit of clothes for the second class; 

 boys in the third class receive no retainer, but the 

 fourth class, consisting of stokers, receive 5 a year. 

 On actual service, after three years whether of 

 uninterrupted service or at broken intervals the 

 volunteer becomes entitled to twopence extra per 

 diem. Th.e man can terminate his engagement 

 at the end of five years, unless on actual ser- 

 vice, when he may oe required to complete five 

 years of such service liefore discharge. During 

 the continuance of his engagement he must 

 not embark on voyages which shall entail a 

 longer absence from the United Kingdom than 

 six months, unless with special permission of the 

 Admiralty. The periods for training are made a* 



