2. Prorocentraceae (Schütt) ( = the Adinida of Bergh); body surrounded by a firm shell of two valves without a girdle band; transverse groove absent; transverse flagellum coiled round base of longitudinal. Exuviaeella (Cienk.) (fig. 2, 3); Prorocentrum (Ehrb.) (fig. 2, 4).
3. Peridiniaceae (Schütt); body with a shell of plates, a girdle band along the transverse groove, in which the transverse flagellum lies. Genera, Peridinium (Ehrb.) (fig. 1), fresh-water and marine; Ceratium (Schrank) (fig. 2, 5, 6), fresh-water and marine; Citharistes (Stein); Ornithoceras (Claparède and Lachmann) (fig. 2, 1).
Literature.—R. S. Bergh, “Der Organismusder Cilioflagellaten,” Morphol. Jahrbuch, vii. (1881); F. von Stein, Organismus der Infusionsthiere, Abth. 3, 2. Hälfte; Die Naturgeschichte der arthrodelen Flagellaten (1883); Bütschli, “Mastigophora” (in Bronn’s Thierreich, i. Abth. 2), 1881-1887; G. Pouchet, various observations on Dinoflagellates, Journal de l’anatomie et de la physiologie (1885, 1887, 1891); F. Schütt, “Die Peridineen der Plankton Expedition” (Ergebnisse d. Pl. Exed. i. Th. vol. iv. 1895); and “Peridiniales” in Engler and Prantl’s Pflanzenfamilien, vol. i. Abt. 2 b. (1896); Zederbauer, Berichte d. deutschen botanischen Gesellschaft, vol. xx. (1900); Delage and Hérouard, Traité de zoologie concrète, vol. i. La Cellule et les protozoaires (1896).
(M. Ha.)
DINOTHERIUM, an extinct mammal, fossil remains of which occur in the Miocene beds of France, Germany, Greece and Northern India. These consist chiefly of teeth and the bones of the head. An entire skull, obtained from the Lower Pliocene beds of Eppelsheim, Hesse-Darmstadt, in 1836, measured 4½ ft. in length and 3 ft. in breadth, and indicates an animal exceeding the elephant in size. The upper jaw is apparently destitute of incisor and canine teeth, but possesses five molars on each side, with a corresponding number in the jaw beneath. The most remarkable feature, however, consists in the front part of the lower jaw being bent downwards and bearing two tusk-like incisors also directed downwards and backwards. Dinotherium is a member of the group Proboscidea, of the line of descent of the elephants.
DINWIDDIE, ROBERT (1693-1770), English colonial governor of Virginia, was born near Glasgow, Scotland, in 1693. From the position of customs clerk in Bermuda, which he held in 1727-1738, he was promoted to be surveyor-general of the customs “of the southern ports of the continent of America,” as a reward for having exposed the corruption in the West Indian customs service. In 1743 he was commissioned to examine into the customs service in the Barbadoes and exposed similar corruption there. In 1751-1758 he was lieutenant-governor of Virginia, first as the deputy of Lord Albemarle and then, from July 1756 to January 1758, as deputy for Lord Loudon. He was energetic in the discharge of his duties, but aroused much animosity among the colonists by his zeal in looking after the royal quit-rents, and by exacting heavy fees for the issue of land-patents. It was his chief concern to prevent the French from building in the Ohio Valley a chain of forts connecting their settlements in the north with those on the Gulf of Mexico; and in the autumn of 1753 he sent George Washington to Fort Le Bœuf, a newly established French post at what is now Waterford, Pennsylvania, with a message demanding the withdrawal of the French from English territory. As the French refused to comply, Dinwiddie secured from the reluctant Virginia assembly a grant of £10,000 and in the spring of 1754 he sent Washington with an armed force toward the forks of the Ohio river “to prevent the intentions of the French in settling those lands.” In the latter part of May Washington encountered a French force at a spot called Great Meadows, near the Youghiogheny river, in what is now south-western Pennsylvania, and a skirmish followed which precipitated the French and Indian War. Dinwiddie was especially active at this time in urging the co-operation of the colonies against the French in the Ohio Valley; but none of the other governors, except William Shirley of Massachusetts, was then much concerned about the western frontier, and he could accomplish very little. His appeals to the home government, however, resulted in the sending of General Edward Braddock to Virginia with two regiments of regular troops; and at Braddock’s call Dinwiddie and the governors of Massachusetts, New York, Pennsylvania and Maryland met at Alexandria, Virginia, in April 1755, and planned the initial operations of the war. Dinwiddie’s administration was marked by a constant wrangle with the assembly over money matters; and its obstinate resistance to military appropriations caused him in 1754 and 1755 to urge the home government to secure an act of parliament compelling the colonies to raise money for their protection. In January 1758 he left Virginia and lived in England until his death on the 27th of July 1770 at Clifton, Bristol.
The Official Records of Robert Dinwiddie, Lieutenant-Governor of Virginia (1751-1758), published in two volumes, at Richmond, Va., in 1883-1884, by the Virginia Historical Society, and edited by R. A. Brock, are of great value for the political history of the colonies in this period.