PLEIADES 274 PLEVNA instruments, etc., may be given in pledge. A living pledge {vadnim vi- vum) is one which produces an income, interest, or profit by being used, and which is retained by the pledgee till he shall have satisfied his claim out of such income, profit, or interest; a dead pledge {vadium mortuum) is a mort- gage. PLEIADES, or PLEIADS, a group of stars in the constellation Taurus, the Bull. The stars are so close together that it is a difficult to say how many are seen by the naked eye. According to mythology, the Pleiades were the seven daughters of Atlas, who, being pursued by Orion, were changed by Jupiter into doves. They were afterward translated to the heavens, where they formed the assemblage of the Seven Stars in the neck of Taurus. PLEONASM, redundancy of language in speaking or writing; the use in speak- ing or writing of more words than are necessary to express an idea. PLESIOSAXTBUS, the typical group of the order Plesiosauria. The skin was naked, the head comparatively small, neck disproportionately long, and the tail short. Teeth conical and pointed, with longitudinal striations, each sunk in an independent socket. The paddles con- sist only of the five digits, without mar> ginal ossicles. It was certainly aquatic; most probably marine, though it may have occasionally visited the shore. Its organization would fit it for swimming on or near the surface, and the length and flexibility of its neck would be emi- nently serviceable in capturing its prey. PLETIIIA, in anatomy, plural, serous membranes forming two shut sacs, each PLESIOSAURUS PLEISTOCENE, a term proposed in 1839 by Lyell as an abbreviation for Newer Pliocene; but Edward Forbes, in adopting it, applied it to the next more modern series of beds, called by Lyell Post-Tertiary. Confusion thus arising, its author withdrew the word, but in the "Student's Elements of Geology," he re- adopted it in the sense of Post-Pliocene. He considers it the older of two divisions of the Post-Tertiary or Quaternary pe- riod. Under it are placed the Reindeer period and the Palaeolithic age generally, the Brick-earth, the Fluviatile Loam or Loess, the High Plateaux Gravel or Loess, the Cavern and the Glacial Drift deposits. The climate was colder than now, the summers hot and short, the winters long and severe. PLENIPOTENTIARY, one who is in- rested with full and absolute powers to transact any business; specifically, an ambassador or envoy accredited to a foreign court, with full powers to negotiate a treaty or to transact other business. possessed of a visceral and a parietal portion. The former {p. pulmonalis) covers the lungs, and the latter {p. costalis) the ribs, the intercostal spaces, etc. The term is used of the air-breath- ing vertebrates in the same sense as above. In the singular form it is ap- plied to the odontophore of the mollusca. PLEtrmSY, inflammation of the pleura, going on to exudation, fluid ef- fusion, absorption, and adhesion. A stitch in the side is complained of, the breathing becomes hurried and shallow, and, as the sero-fibrinous deposit becomes greater, intense dyspnoea sets in, with a short, dry, hacking cough. PLEURO-PNEUMONIA, pneumonia with bronchitis, the former constituting the chief disease. PLEVNA, a town of Bulgaria, 19 miles S. of the Danube and 85 N. E. of Sophia. Here in 1877 Osman Pasha, the Turkish general, after defeating the Rus- sians in several engagements, intrenched himself. After making an unsuccessful
