PAL 



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PAL 



and flr/pt'ov, a wild beast, Gr.) An ex- 

 tiuct genus of fossil quadrupeds, belong- 

 ing to the order Pachydermata, having 

 twenty-eight molar teeth, or grinders, six 

 incisors, and two canine teeth in each 

 jaw. It possessed three toes to each foot, 

 and had a short fleshy proboscis. Eleven 

 or twelve species of the genus have been 

 discovered. " The place of the genus Pa- 

 Iseotherium," says Prof. Buckland, "is 

 intermediate between the rhinoceros, the 

 horse, and the tapir. Some of the dis- 

 covered species were as large as a rhi- 

 noceros, others were from the size of a 

 horse to that of a hog. These animals 

 probably lived upon the margins of the 

 then existing lakes and rivers. 

 PAL^EOTHE'RIAN. Belonging to the genus 

 Palseotherium, as palseotherian remains, 

 &c. 



PA'LEA. (palea, chaff, Lat.) In botany, 

 a term applied to the two inner bractese of 

 grasses : the palese are membranous or 

 chaffy in texture. 



PALLA'DIUM. (from the planet Pallas.) A 

 metal of a greyish or bluish-white colour, 

 discovered by Dr. Wollaston in 1803, in 

 platinum. It is malleable, ductile, and 

 flexible, but does not possess much elas- 

 ticity. In hardness it surpasses all other 

 metals, with the exception of tungsten, 

 which it equals. Specific gravity 11 '5. 

 It is not oxidated by the action of the 

 atmosphere. It is fusible only at a very 

 high temperature. 



PA'LLEAL. (from pallium, a mantle, Lat.) 

 In conchology, the name given to the 

 mark or impression observed in bivalves, 

 formed by the muscular attachment of the 

 mantle. 



PA'LMATE. } (palmatus, Lat.) Webbed, 

 PA'LM ATED. S like the feet of some water- 

 birds ; deeply divided into lobes like the 

 fingers on the hand ; resembling a hand ; 

 palmed or hand-like. Applied to leaves 

 which are divided, half, or more than half- 

 way, down the middle, into several nearly 

 equal segments, having a space between 

 each. 



PA'LMIPEDES. (from palmipes, that hath 

 its feet closed with a film or web, Lat. 

 The sixth order of birds in Cuvier's ar- 

 rangement. The goose and duck are 

 familiar examples. 

 PALM, (from palma, Lat.) The palms 

 constitute a natural order of monocotyle- 

 donous, or endogenous, plants. The 

 flowers are hermaphrodite, or polyga- 

 mous. Perianth six-parted, persistent 

 Stamens inserted into the base of th 

 perianth, definite or indefinite. Ovary 

 three-celled, or deeply three-lobed, witi 

 an erect ovule. Fruit baccate or dru 

 paceous, with fibrous flesh. Albumen 

 cartilaginous ; embryo in a cavity at 



distance from the hilum. Leaves ter- 

 minal, large, pinnate, or flabelliform, 

 plaited in vernation. Spadix enclosed 

 in a valved spatha. Flowers small. 



A palm tree affords an example of the 

 mode of growth in endogenous plants. 

 The stem of this tree is usually perfectly 

 cylindrical, attains a great height, and 

 bears on its summit a tuft of leaves. It 

 is composed of an extremely dense ex- 

 ternal cylindric layer of wood ; but the 

 texture of the interior becomes gradually 

 softer and more porous as it approaches 

 the centre. It has neither medullary 

 rays, nor central pith, nor true outward 

 bark. The first stage of its growth con- 

 sists in the appearance of a circle of 

 leaves, which shoot upwards from the 

 neck of the plant, and attain, during the 

 first year, a certain size. The following 

 year another circle of leaves arises ; but 

 they grow from the interior of the former 

 circle, which they force outwards as their 

 vegetation advances, and as ligneous 

 matter is deposited within them. As 

 soon as the outer layer has become too 

 hard to yield to the pressure from within, 

 the growth of the inner layers is imme- 

 diately directed upwards ; so that they 

 rise in succession by distinct stages, al- 

 ways proceeding from the interior ; a 

 mode of development which has been 

 compared by De Candolle to the draw- 

 ing out of the sliding tubes of a telescope. 

 The whole stem, whatever height it may 

 attain, never increases in diameter after 

 its outer layer has been consolidated. A 

 circle of leaves annually sprouts from the 

 margin of the new layer of wood ; these, 

 when they fall off, leave traces, consisting 

 of a circular impression, round the stem. 

 By the number of these circles the age of 

 the tree may be ascertained. The ex- 

 isting family of palms is supposed to con- 

 sist of nearly a thousand species, of 

 which the greater number are limited to 

 peculiar regions of the torrid zone. It is 

 not surprising to find the remains of 

 palms in warm latitudes, where plants of 

 this family are now indigenous ; beau- 

 tifully silicified stems of palm trees 

 abound in Antigua, and in India ; but 

 their occurrence in the tertiary forma- 

 tions of Europe, associated with the re- 

 mains of crocodiles and tortoises, and with 

 marine shells, nearly allied to forms now 

 found in seas of a warmer temperature, 

 seems to indicate that the climate of 

 Europe, during the tertiary period, was 

 warmer than at the present time. The 

 palms have pervaded all the series of for- 

 mations, though in small proportions. 

 PA'LPI. In entomology, the palpi, or 

 feelers, are the auxiliary organs of a mas- 

 ticating mouth. Those upon the max- 

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