PEL 



L 346 3 



PEN 



from other causes, at the bottom of 

 the sea. 



PEL'DON. "We can sometimes trace 

 sandstone becoming finer and finer, 

 till we arrive at a rock for which 

 we have no very accurate or dis- 

 tinctive name, a flinty or silicious 

 rock, with a perfectly smooth com- 

 pact texture, a conchoidal fracture, 

 without anything we could call a 

 grain. A rock of this kind, when 

 . met with in the coal-measure of 

 S. Staffordshire, is there called a 

 peldon, and I venture to propose 

 that designation for the acceptance 

 of my brother geologists. 'Jukes. 

 PE'LIOM. (from ire\itofiM t Gr. blue- 

 ness, or of a lead colour.) A blue 

 coloured mineral resembling iolite, 

 of which it is a variety. It is 

 found in Bavaria. 



PE'LLICLE. (from pellicula, Lat.) A 

 film ; a thin crust or covering. 



In botany, a membranous or 

 mucilaginous covering, closely ad- 

 hering to the outside of some seeds, 

 so as to conceal their proper surface 

 and colour. 



PELTA'TE. (from pelta, Lat. a target.) 



In botany, a term applied to leaves 



which have their footstalk inserted 



in the middle of the leaf, and not 



joined to the edge ; the nasturtion 



is a familiar example. 



PE'LVIS. (pelvis, Lat. from we'Xvs, 



Gr. a basin.) The lower part of 



the trunk of vertebrated animals. 



PE'NCIL. A name given to the belem- 



nite. 



PE'NNATE. j (pennatus, Lat. from pen- 

 PE'NNATED. j na t awing.) Winged; 



feathered. 



PENNA'TITLA. Called, commonly, the 

 Seapen. A polypus with a calca- 

 reous axis or stem, having a double 

 set of branches extending in the 

 same plane from both sides, like 

 the vane of a quill. Pennatula3 are 

 not fixed by any attachment to 

 the ground, but float about in the 

 waters of the ocean, carried hither 



and thither as the current may 

 direct them. 



PE'NNIFORM. (from penna, a feather, 

 and. form.) Having the form of a 

 feather or quill. In anatomy, 

 muscles in which the muscular 

 fibres pass obliquely outwards on 

 either side from a tendinous centre, 

 are termed penniform. The rectus 

 femoris affords an illustration of a 

 penniform muscle. 



PENTACA'PSULAE. (from TreVre, Gr. 

 five, and capsular, Lat. a cell or 

 capsule.) Having five cavities, 

 capsules, or cells. 



PENTA'CEROS EETICTJLA'TTJS. A fossil 

 species of asteria, or stella marina. 



PENTA'CEROS DENTIGINO'SUS. A fossil 

 species of asteria or stella marina, 

 found in the chalk and in the Lon- 

 don clay. 



PENTACRI'NEA. A tribe of stone-lilies, 

 comprising the living genus Penta- 

 crinus (including Chladocrinus and 

 Extracrinus) and the extinct genus 

 Isocrinus. 



PENTA'CRINITE. The fossil Pentacrinus. 



PENTACRI'NTJS. (from TreWe, five, and 

 encrinite.) The five angled lily- 

 shaped animal. A genus of the 

 family Crino'idea. Miller thus de- 

 scribes the generic character of 

 pentacrinus. " An animal with a 

 column formed of numerous pent- 

 angular joints, articulating by sur- 

 faces with pentapetalous semi- 

 striated markings. Superior colum- 

 nar joint supporting a pelvis of 

 five joints, on which five first 

 costals rest, succeeded by five 

 second costals and five scapula, 

 from which ten arms proceed, 

 having each two hands, composed 

 of several tentaculated fingers. 

 Column long, having numerous 

 auxiliary side arms. Base unas- 

 certained." The arms, when ex- 

 panded, resemble a star of five (or 

 six) rays ; and when they converge, 

 a pentapelous or hexapetalous flow- 

 er. The whole animal, when alive, 

 is supposed to be invested with a 



