Glossary of Morphological and Anatomical Terms
palintrope - Originally used for morphologically posterior sector of either valve that was reflexed to grow anteriorly (mixoperipheral growth); more recently used for curved surface of shell, bounded by beak ridges and cardinal margin of astrophic shells (differs from planarea in being curved in all directions).Fig.285.
pallial caecum - See caecum.
pallial lobe - See mantle.
pallial sinus - See mantle canal.
papillae - See endospines.
paraendopunctae - See extropunctae.
parathyridium - Deep, pouchlike indentation of shell on either side of beak formed by medially directed depression or flexure of posterolateral shell surface of both valves, particularly dorsal (e.g., Cardinarina).
parvicostellate - Costellae numerous, arising entirely by intercalation between widely spaced costae.Fig.297.
paucicostate - Costae distant from umbo and few.
paucicostellate - Costae and costellae distant and few.
paucispinose - Very few spines.
pedicle callist - Localized thickening of secondary shelllayer in apex of ventral valve representing track ofanterior migration of junction between pedicle epithelium and outer epithelium.Fig.348.
pedicle capsule - Cylindroid infold of pedicle epithelium and cuticle accommodating the proximal bulbous end of the pedicle of articulated brachiopods.Fig.1.
pedicle collar - Complete or partial, ringlike thickeningof inner surface of ventral beak continuous laterallywith internal surface of deltidial plates sessile, withseptal support, or free anteriorly and secreted byanteriorly migrating outer epithelium at its junctionwith pedicle epithelium.Fig.316.
pedicle foramen - Subcircular to circular perforation of shell through which pedicle passes.Fig.317.
pedicle fulcrum - Pair of subparallel plates median todental plates in ventral umbo of some early athyridines.
pedicle furrow - External plate extending anteriorly frombeak to pedicle foramen in some siphonotretoidsand obolellides.
pedicle groove - Subtriangular groove dividing ventralpseudointerarea medially and affording passage forpedicle in many lingulides.Fig.286.
pedicle muscle scar - Scar of attachment on ventral valveof longitudinal fibrils in connective tissue of pedicleof articulated brachiopods.
pedicle muscles - Muscles associated with pedicle external to pedicle in articulated brachiopods (adjustor and median pedicle muscles); internal in inarticulated brachiopods.
pedicle notch - Small, subtriangular depression, posteromedially placed on limbus of paterulids, probably functioning as pedicle groove.
pedicle opening - Variably shaped aperture in shellthrough which pedicle emerges.
pedicle plate - Tongue-shaped shelly deposit inside labiate foramen.
pedicle tube - Internally directed tube of secondaryshell continuous with margin of pedicle foramenand enclosing proximal part of pedicle.Fig.310.
pedicle valve - See ventral valve.
perideltidial area - Discrete part of perideltidium.
perideltidial line - Break of slope marking outer boundary of perideltidial area.
perideltidium - Pair of slightly raised triangular parts ofinterarea flanking pseudodeltidium or lateral to itand characterized by vertical striae in addition to horizontal growth lines parallel to posterior margin characteristic of orthotetidines.
periostracal pad - Thickened band of periostracum covering cardinal areas and spun out by fused mantle lobes along posterior margin of some articulated brachiopods.Fig.44.
periostracum - Organic external layer of shell secreted by the outer mantle lobe beneath an impersistent film of glycosaminoglycans and acting as the seeding sheet for the primary mineralized shell.Fig.2.
planareas - Two flattened areas developed, one on either side of posterior part of shell, more or less perpendicular to commissural plane single median interarea may be much reduced or absent.
plane commissure - See rectimarginate.
planoconvex - Dorsal valve flat; ventral valve convex.
plate - Single transverse, platelike projection from cardinal margin of dorsal valve articulating with cardinal socket of ventral valve.Fig.375.
platform line - Side bounding notothyrial chamber.
platform vaults - Two cavities beneath platform in some trimerelloids, separated by median partition.Fig.375.
platidiiform - Loop consisting of descending lamellae from cardinalia to median septum occasionally with only rudimentary outgrowths from distal end of septum analogous to ascending lamellae.
plectolophe - Lophophore in which each brachium consists of U-shaped side arm bearing double row of paired tentacles but terminating distally in medially placed planospire normal to commissural plane and bearing single row of paired tentacles.Fig.114.
plectolophus - See plectolophe.
pleuromal plates - Pair of plates in posterior part of delthyrial cavity of some spiriferides immediately internal to dental plates probably merely later infilling of delthyrial cavity.
pliciligate stage - See parasulcate.
polypalmate - Mantle canal system with more than four principal canals in each mantle.
posterior - Direction in plane of symmetry or parallel to it toward pedicle and away from mantlecavity.Fig.283.
posterior flap - Reflexed to anteriorly directed extensionof lyttoniid ventral valve lying dorsal to at least posteromedian part of dorsal valve.
posterior margin - Posterior part of junction betweenedges of valves; may be hinge line or cardinal margin.Fig.285.
posterior oblique muscles - Pair of muscles indiscinoids originating posterolaterally on ventralvalve and converging dorsally to insertions on dorsal valve between posterior adductors; equivalent tooblique internals.Fig.374.
pre-ismeniform - See diploform.
precampagiform flange - See septal flange.
precampagiform hood - See hood.
prefalcifer - See hamiform.
premagadiniform - One of the early stages of terebratellide loop development marked by growth ofdescending branches from both cardinalia and median septum and their completion and by the appearance of tiny hood developing into ring on septum.
prepygites stages - See plicosulcate.
presocket line - Anterior or anterolateral side of triangular slot produced by brachiophore plate (and fulcralplate if present) in internal mold of orthides.
primary layer - Outer, mineralized shelllayer immediately beneath periostracum depositedby vesicular cells of outer mantle lobe.Fig.11.
prismatic shell - Band or continuous layer of polygonalcolumns of calcite disposed normal to the shell surface.
prodeltidium - So-called third plate at one time thoughtto be developed in earlier embryonic growth ofatrematous, neotrematous, and protrematous species (BEECHER, 1891, 1892), subsequently becoming more or less attached to either dorsal(atrematous) or ventral valve.
promontorium - Shelflike structureextending laterally from lateral sloping face of cardinal process homologue of inner socket ridges insome orthotetidines.
propareas - Pair of subtriangular halves of pseudointerarea divided medially by various structures(e.g., homeodeltidium intertrough and pediclegroove) of inarticulated brachiopods.Fig.286,Fig.327_1.
propuncta - See pseudopunctum (proposed for deflections without taleolae).
prosocket ridge - See socket ridge.
prostrate spines - Usually straight spines that lie proneon shell surface of some productides.
protegulal node - Apical portion of adult shell, commonly raised, representing site of protegulum andlater growth up to neanic stage.Fig.297.
protegulum - First-formed shell of periostracum andmineralized lining secreted simultaneously by bothmantles.Fig.283.
protractor muscles - See outside lateral muscles middle lateral muscles in inarticulated brachiopods; also used for longitudinal fibrils attached to setae and those in the connective tissue of pedicle of articulated brachiopods; See pedicle muscle scar.
pseudoarea - See pseudointerarea.
pseudobrace plate - Tuberculate ridges bearing dorsal adductor muscles.
pseudochilidium - See chilidium.
pseudocruralium - Callus of secondary shell bearing dorsal adductor impressions and elevated anteriorly above floor of valve.Fig.366.
pseudodeltidium - Single, convex, or flat plate affording variably complete cover of delthyrium but invariably closing apical angle when foramen is supra-apical or absent and always dorsally enclosing apical foramen.Fig.319,Fig.327_1,Fig.327_3,Fig.353.
pseudointerarea - Somewhat flattened, posterior sector of shell of some inarticulated brachiopods secreted by posterior sector of mantle not fused with that of opposite valve.Fig.286.
pseudopedicle collar - Sessile pedicle collar.
pseudopedicle groove - See intertrough.
pseudopunctum - See pseudopuncta.
pseudoresupinate - Convexoconcave shell.
pseudosocket - See secondary sockets.
pseudospondylium - Cup-shaped chamber accommodating ventral muscle field and comprising undercut callus of secondary shell contained between discrete dental plates.Fig.352.
pseudoteeth - See secondary teeth.
pseudotelae - Pair of external projections resembling telae but produced by dorsal migration of pedicle cutting labiate foramen not beak ridges.
ptycholophe - Lophophore with brachia folded into one or more lobes in addition to median indentation.Fig.115.
ptycholophus - See ptycholophe.
puncta - Perforation penetrating shell to connect with periostracum and occupied by caecum as in cranioids; any perforation apparently penetrating fossil shell and large enough to accommodate caecum.Fig.261.
