RODENTIA 



RODNEY 



a normal day's work, and a maximum and mini- 

 mum of wages. His views are laid down in Zur 

 Kenntniss unserer staatswirthschaftlichen Zustmide 

 <1842), Soziale Briefe (1850-51 and 1884), Zur 

 Erklarung der Kreditnot des Grundbesitzes ( 1868- 

 69), 'Der Normalarbeitstag ' and other papers in 

 Tubintjer Zeitschrift (1878 et seq.), and others in 

 Jahrbiicherfur Nationalckonomie. 



His Briefe und Auffdtze were edited by R. Meyer 

 (2 vols. 1882), and his Kleinere Schriften by M. Wirth 

 (Berlin, 1890). See monographs by K. Adler (1884) and 

 Dietzel ( 1886-88 ). See also SOCIALISM. 



Rodentia ( Lat. ' gnawers ' ), an order of 

 Mammals more rich in species than any of the 

 others, including among its familiar representa- 

 tives squirrels, marmots, beavers, rats and mice, 

 lemmings, porcupines, guinea-pigs, hares and 

 rabbits. Most are terrestrial, and many are 



Skull of Common Porcupine ( Hystrix cristate) : 

 The lower jaw partly in section to show the lower incisor tooth. 



burrowers, but a few are arboreal or even semi- 

 aquatic. All are vegetarian, and gnaw their food. 

 Tney are represented in all parts of the world. 



Among the anatomical characteristics of Rodents 

 may be noted the chisel-like edge of the incisor 

 teeth, which wear away in front less rapidly than 

 they do behind, where the enamel coating is thinner 

 or absent ; the reduction of the incisors to two 

 above and two below, except in the hares and 

 rabbits, in which there are four above ; the fact 

 that the incisors and sometimes the back teeth also 

 are rootless, and continue growing from persistent 

 pulps ; the al>sence of canine teeth, and the presence 

 of a large space between incisors and premolars ; 

 the comlyle in which the lower jaw works is 

 elongated from before backwards an adaptation 

 to the peculiar motion of the lower jaw character- 

 istic of rodent gnawing; the cerebral hemispheres 

 are smooth, and leave the cerebellum uncovered ; 

 the intestine, as in many herbivorous animals, has 

 a large Ciecum ; the uterus is two-horned, the 

 placentation discoidal atid deciduate ; the repro- 

 duction is in many cases very prolific. 



Classification. Sub-order Simplicidentata with 

 only one pair of upper incisors, having enamel only 

 in front. This sub-order includes squirrels (Sciurus), 

 flying squirrels (Pteromys and Sciuropterus), 

 marmots (Arctomys), leavers (Castor), dormice 

 <Myoxid;e), rats ami mice, voles, lemmings, musk- 

 rats (Muridie), pouched-rats (Geomyidse), thecapy- 

 bara (Hydrochaerus), porcupines ( Hystricida? ), 

 agoutis ( Dasyprocta ), guinea-pigs (Cavia). Sub- 

 order Duplicidentata with two pairs of incisors in 

 the upper jaw, the second pair behind the first, the 

 enamel extending round the teeth, but thinner 

 posteriorly. This sub-order includes only the 

 Picas or tailless hares (Lagomys) and the hares 

 and rabbits (Li-pus). 



See Waterhouse, Natural Hillary of the Mammalia., 

 ToL ii. 'Kodentia' (1848); Flower and Lydekker, 

 Mammalt, Living and Extinct (land. 1891). 



Roderic, ' the last of the Goths," whose 

 tragic death, coincident with the downfall of the 



Visigothic monarchy in Spain, has inspired poets 

 and romancers (Scott, Southey, Geibel, Dahn) 

 to throw round him a halo of glory. Next to 

 nothing authentic is known about him ; but 

 according to the commonly accepted legend, he 

 was the son of a noble who was blinded by King 

 Witiza. A conspiracy having been formed against 

 the hated Witiza by the clergy and the nobles of 

 Roman blood, Roderic was elevated to the throne 

 (710). The sons of Witiza, however, bided their 

 time, meanwhile submitting to the usurper. At 

 length certain malcontent nobles were engaged in 

 a plot to dethrone Roderic by Count Julian, the 

 governor of Ceuta ( in North Africa ), whose daughter 

 had been outraged by the Visigothic king. Julian 

 brought over with him a Moorish chief named 

 Tarik at the head of 12,000 men. Roderic met the 

 invading army on the banks of the Guadalete, near 

 Xeres de la Frontera, on 26th July 711. The battle 

 raged six days ; but the sons of Witiza, who com- 

 manded the wings of the Christian army, deserted 

 during the contest, and the rout of the Visigoths 

 was complete. Roderic either died on the field or 

 was drowned in the Guadalete, whilst attempting 

 to swim his horse across. A third version, how- 

 ever, relates that he escaped and passed the rest of 

 his life as a pious hermit. By this victory the 

 Arabs became masters of southern Spain. 



Rodez. a town of southern France (dept. Avey- 

 ron ), stands on a bold bluff encircled by the Avey- 

 ron, 148 miles by rail NW. of Montpellier. The 

 Gothic cathedral') 1277-1535) has a tower, 260 feet 

 high, crowned by a colossal image of the Virgin. 

 There are several mediaeval houses, remains of a 

 Roman amphitheatre, and a restored Roman 

 aqueduct. Coal-mining, cloth-making, tanning, 

 and cattle-dealing are the principal occupations. 

 Pop. (1872) 12,111; (1886) 14,560; (1891) 12,065. 



IJo<lii'rs. JOHN, American naval officer, was 

 born in Maryland, llth July 1771, the son of a 

 Scotch colonel of militia. He was a captain in the 

 merchant service by 1789, and in 1798 entered the 

 navy. In 1805 he extorted from Tripoli and from 

 Tunis treaties abolishing blackmail and forbidding 

 the slavery of Christian captives. On 23d June 

 1812 he fired with his own hand the first shot in 

 the war with Britain, and during the war he took 

 twenty-three prizes. He died 1st August 1838. 

 His son, JOHN RODGERS ( 1812-82), a captain in the 

 navy, captured a Confederate ironclad, and rose to 

 be rear-admiral (1869), and superintendent of the 

 United States naval observatory ( 1877). 



Rodin, AUGUSTE, the foremost of contemporary 

 French sculptors, was born at Paris in 1840, studied 

 under Barye, and began to exhibit in the Salon in 

 1875. He has produced great scriptural and sym- 

 bolical groups, but is best known by his portrait 

 busts and statues, notably the bust and the monu- 

 ment of Victor Hugo. See Monkhouse in the Port- 

 folio ( 1887 ) ; and Brownell, French Art ( 1894 ). 



Rodman, THOMAS JEFFERSON (1815-71), an> 

 American soldier, inventor of a method cf casting 

 cannon. See article CANNON, Vol. II. p. 714. 



Rodney, GEORGE BRYDGES RODNEY, LORD, 

 English admiral, born 19th February 1719, was the 

 second son of Henry Rodney, a cadet of an 

 ancient Somersetshire family, the elder branch of 

 which had merged in that of Brydges, and was at 

 this time represented by the first Duke of Chandos. 

 Henry Rodney served for a few years as cornet of 

 horse in the wars of William III. and Anne, and 

 afterwards, settling at Walton-on-Thames, obtained 

 an appointment under George I. as commander of 

 one of the royal yachts. In this capacity he was 

 noticed by the king, who offered to stand as god- 

 father to his second son. The Duke of Chandoa 

 was the other godfather, and after the two the boy 



