PLENER, ERNST, FREIHERR VON (1841-1923), Austrian politician, was born on Oct. 18, 1841, at Cheb in Bohemia, the son of the Austrian statesman Ignaz von Plener (1810-1908). From 1888 onwards he was the acknowledged head of the Ger man Liberals in their struggles against the Slav-Conservative majority in the Chamber. Consequently he represented Ger manism on the nationalities question, but was not averse to They first appear in the Rhaetic and are last seen in the Upper Cretaceous. A typical plesiosaur has a small head with a large mouth and slender pointed teeth adapted to the catching of fish. The neck is long, often f our times as long as the head. The body is relatively short, as is the tail. All four limbs are converted into paddles, no external trace of the fingers being visible.
From these forms two main evolutionary lines appeared. In one, the animals adopted the habit of living on large prey which they captured by their superior speed ; in this line the head grew bigger and the neck shorter until it became no longei- than the head. The body is comparatively long, the tail little more than the pointed hinder extremity of the body. The paddles become very large indeed, the hinder pair being bigger than the front ones. The
largest members of this group are the plesiosaurs from the Euro pean Jurassic. In them the skull may be nearly 6 ft. in length and an individual tooth a foot long. In an animal whose head was just under 5 ft. in length the whole creature had a length of some 16 ft., and the hind paddles were about 5 ft. long.
The other line consists of animals which fed on small quick moving prey which they seem to have captured by sudden lateral movements of the head and neck. Its most recent member, Elasmosaurus, is found in the Upper Cretaceous of Kansas, Eng land, Queensland and New Zealand. In it the head is about 18 in. in length, the neck with as many as 76 vertebrae may reach a length of 19 ft., and the total length of the animal about 30 ft. The paddles of such an animal were about 3 ft. in length. Some plesiosaurs had the interesting habit of eating pebbles which were kept in the stomach to assist in grinding up food. Although the majority of plesiosaurs were marine, some few are always found in estuaries or freshwater deposits. See REPTILES.