TrF.Tl.WTT CBAB. 8 HEKMIT THRUSH. often remain in a single shell for a long time, bo that colonies of Uydractinia and oilier lij- droiJs grow over a large part of it. Often sea- anemones attach themselves to the shells in which hcnnit crabs live, and thus get the benefit of free and rapid transportation. (See Comme-n- SALlsM.) . Chinese species is said to carry an aneiiKine on its claw, so that when withdrawn into its shell the anemone forms an effectual stop- per to the opening. Increase of size, however, ren- ders it necessarj' for hermit crabs to relinquish their shells and seek new ones from time to time, and when thus engaged they are very interest- ing animals to watch. They try on shell after shell before finding one that suits them, and they are constantly quarreling savagely over their houses; yet in fact they are great cowards. Her- mit crabs are very interesting inmates of the aquarium, but their locomotive habits and their voracity make them unsuitable for an aquarium stocked with valuable animals. They feed on mollusks and other crustaceans, and all the ani- mal garbage of the seashore. The most conmion American species (Pagtirus lonflicarpus) is an interesting object to every visitor of the seashore, and may be foimd in abundance wherever little pools are left by the tide on a rocky or shelving coast, from Jlassa- chusetts Bay to South C/nrolina. This species never reaches a large size, and is usually under an inch in length. It is very gregarious, and large numbers are usually found together. A closely related larger species is Ku- pafiurus poUirnris, which is fmin<l in shallow water from Massachusetts to Florida, inhabiting the shells of atica and other gastropods. The common Euro|)ean species. Eupiirfiini/i lirrnhar- dus, is also found in somewhat deeper water off the northeastern coast of America. In the tropics some interesting forms occur, including one or two of large size. One of the most interesting is the Diogenes crab (Vccnohita Diogenrs) . which is several inches long when fully extended. It lives on land, and is found in the driest places. Hs active as other forms are in the sea. .llied to the hermit crabs are the palm or robber cral>s {liirqtts lairo) of the East Indies, which live in holes in the ground at the foot of cocoanut palms, on the fruit of which they feed. They do not carry a shell with them. See Land-Cr.b. While the shallow-water hermit crabs are sym- metrical behind the thor.TX, in certain deep-sea forms the abdomen is sjTnmetrical, .showing that the ancestors of the ordinary hermit crabs were all symmetrical. PoU/chrlm Aqaasizii of the West Indian seas lives in straight tubes of com- pacted .«and, the abdomen being symmetrical. This also is the ease with Xi/lopaguriis rectus, living in open tubes of wood or bamboo stem. Tylaspis anomnln. inhabiting the South Pacific at a depth of 2,'?75 fathoms, has a shortened but symmetrical abdomen, with distinct segments and symmetrical legs. Another form (Chfenopagu- rus) takes refuge in a sheet or blanket formed by the ctenosarc of a colony of polyps. It also is symmetrical. The polyp (Zoanthus) is tucked by the crab under its telson by one end and pulled ovei its back by the other, and the two animals, crab and polyp, seem incapable of independent existence. (See CoMMUNSALtsM.) Hermit crabs have rarely been found in a fossil state, and then only their claws are found preserved. These have been obtained in the Eocene rocks of Hun- gary. Consult: Emerton, Life on the Heaahure (Salem, 188U) ; Verrill, Inicrtebrutvs of Vine- yard Hound (Washington, 1874) ; Arnold, Sea Hiach at Ebb Tide (New York, I'.tOl); Milne- Edwards et Bouvier, "Description des crustacte de la famille des Pagurieus pendant I'Kxpddition de la Blake" {Memoirs Museum of Comparative- Zoology, Cambridge, 189;)). HEH.MITE, armC-t', Charles (1822-1901;. One of the bc>t-known l""rench mathematicians ot the nineteentli century, lie was born at Dicuze, Meurthe, and received his early education in the Lyi'ee Louis-letlrand. He entered the Ecolo Polytechnique in 1842, but left at the end of the year, in order to devote his attention exclusively to mathematics. From 1848 to 1870 he was connected with the Ecole Polytechnique in various capacities, and from 18(!2 to 1873 was maitre de conf<^rences in the Ecole Xormale Sui)erieure. From 187(5 until his death he gave his time to the university, where he held the chair of higher algebra (1800-97). He was a mcml)er of the Academy of Sciences, and a grand oflicer of the Legion of Honor (1892). His work was chiefly along the line of theory of functions, in which subject he was for many years the leader in France. His first great work, the one which secured for him his election to the Academy of Sciences, was Sur la thforie de la transformation des fonctions abclienncs {('omptes rcndus, 1855). At about the same time begin his discoveries in the new theory of algebraic forms and in the theory of numbers. His most remarkable mem- oirs, twenty-si.x in number, Sur quclt/ues appli- cations de la thforie des fonctions elliptiques, appeared in the Coniptcs rcndus (1877-82). His memoir,.9ur IVguation du acme degri^ () , may be said to have finally settled the great question of the solubility of the quintic equation to the entire satisfaction of the mathematical world. His memoir iSiir la fonction expont-nticlle (1874), in which he proved the incommensurability of e. paved the way for I.indcmann's proof (1882) of the incommensurability of -r. Hemiite was a. very prolific writer, A substantially complete list of his memoirs may be found in the Catalogue of Scientific Papers of the Royal Soc^ty of London, vols, iii, and vii. Besides his memoirs, which contain his most valuable contributions, he published a Cours d'analyse de VKcole Poly- technique (187.3; 2d ed. 1894"). and assisted Ser- ret in editing Lacroix's calculus (0th ed., Paris, 1881, 2 vols.) . Consult articles by Mittag-Lefflcr and Picard in .4c(a Mathenmtica, vols, xxiii., x.xiv. (Stockholm, 1901-02). HEKMIT HUMMING-BIRD. A name given to a group of huniniingliirds which agree in having the beaks much curved, and the edge of the mandibles not serrated. The 'true' hermit* are of the genus Phaethornis, whose sixteen spe- cies are found from Mexico to Southern Brazil, mostly in the hot lowlands. The 'sickle-billed' hermits of the genus Euto.xeres have the beak greatly bent downward, sometimes describing a full half-circle. The whole group keep them- selves secluded in dense forest, whence the name. Sec III MMixfi-BiRii. HERMIT KINGDOM. A popular name given to Knrea (q.T.). HERMIT THRUSH. See Thrush.
