PRI- 



255 



PRO- 



apo, from ; physis, growth.] A 

 process on the anterior face of the 

 neural arch for articulation with 

 the vertebra in front (anat.). 



prickle (prik'l) n. [A.S. prica, a 

 point.] A pointed process arising 

 through epidermal tissue (bot.). 



prickle cells, cells of the deeper 

 layers of stratified squamous 

 epithelium : they have short, 

 fine, marginal, connecting fibrils 

 (anat.). 



primary (prl'mari) a. [L. primus, 

 first.] First ; principal ; original ; 

 appl. axis, feathers, meristem, root, 

 wood (biol.). 



primaxil (primak'sil) n. [L. primus, 

 first ; axilla, armpit.] The first 

 axillary arm of a Crinoid (zool.). 



primibrachs (pri'mibraks) n.plu. [L. 

 primus, first ; brachia, arms.] In 

 Crinoids, all brachials up to and 

 including the first axillary (zool.). 



primine Qpri'min) n. [L. primus, 

 first] The external integument 

 of an ovule ; occasionally appl. the 

 first-formed or internal coat (bot.). 



primite (prim'it) n. [L. primus, first.] 

 The first of any pair of individuals 

 .of a catenoid colony in the pseudo- 

 conjugation of Gregarinida, in 

 which the protomerite of one (the 

 satellite) becomes attached to the 

 deutomerite of another (the primite) 

 (zool.). 



primitive (prim'itiv) a. [L.primitivus, 

 early.] Of earliest origin ; appl. 

 groove, knot, streak, aorta, palate, 

 ventricle (emb.). 



primordial (prlmdr'dial) a. [L. prim- 

 ordium, a beginning.] Primitive ; 

 original ; first commenced ; appl. 

 ova (emb.), cell, utricle (hot.). 



primordium (primor'dmm) n. [L. 

 primordium, a beginning.] Original 

 form ; a structure when first in- 

 dicating assumption of form ; 

 anlage (emb). 



priodont (prfodont) a. [Gk. prion, 

 saw ; odous, tooth.] Saw-toothed ; 

 appl. stag-beetles with smallest 

 development of mandible projec- 

 tions (zool.). 



prismatic (prizmat'lk) a. [L. prisma, 

 prism.] Like a prism ; appl. leaves 

 (bot.) ; consisting of prisms, as the 

 prismatic layer of shells (zool.}. 



proamnion (proam'nlon) n. [Gk. 

 pro, before ; amnion, a vessel for 

 receiving blood.] An area of blasto- 

 derm in front of the head of early 

 embryos of higher vertebrates 

 (emb). 



proangiosperm (proan'jIospSrm) n. 

 [Gk. pro, for ; anggeion, vessel ; 

 sperma, seed.] A fossil type of 

 angiosperm (bot.). 



proatlas (proat'las) n. [Gk. pro, 

 before ; Atlas.'] A median bone 

 intercalated between atlas and 

 skull in certain Reptiles (zool.). 



proboscidiform (pro'bosid'iform) a. 

 [Gk. proboskis, trunk ; L. forma, 

 shape.] Proboscis-like ; appl. In- 

 fusorians with tentacles on a pro- 

 boscis-like process (zool.}. 



proboscis (probos'Is) n. \Gk. proboskis, 

 trunk.] A trunk-like process of 

 the head, as of Insects, Annelids, 

 Nemerteans, Elephants (zool.}. 



procambial strand, a longitudinal 

 strand of elongated cells near the 

 periphery of the plerome of a 

 vascular bundle ; a desmogen 

 strand (dot.). 



procambium (prokam'blum) n. [L. 

 pro, before ; L.L. cambium, nutri- 

 ment.] The tissue from which 

 vascular bundles are developed 

 (bot.). 



procarp (pro'karp) . [Gk. pro, for ; 

 karpos, fruit.] The female organ 

 of red Seaweeds, a one or more 

 celled structure containing no differ- 

 entiated oosphere (bot.). 



process (pro'sgs) n. [L. pro, forth ; 

 cedere, to go.] An outgrowth, pro- 

 longation, projection, or eminence 

 of any structure. 



processus, a process. 



prochorion (proko'riSn) n. [Gk. pro, 

 before ; chorion, skin.] An envelop- 

 ing structure of the blastodermic 

 vesicle preceding formation of a 

 chorion (emb.). 



prochromatin (prokro'matln) n. [Gk. 

 Pro, for ; chroma, colour.] Plasmo- 

 some substance (cyt.). 



procoelous (prose'lus) a. [Gk. pro, 

 before ; koilos, hollow.] With con- 

 cave anterior face, as vertebral 

 centra (zool.). 



procoracoid (prok6r'akoid) n. [Gk. 

 pro, before ; korax, crow.] An 



