PRO- 



260 



PRO- 



protomerite (pr6t6m'6rit) n. [Gk. 

 protos, first ; meros, part.] The an- 

 terior part of the medullary proto- 

 plasm of adult Gregarines ; cf. 

 deutomerite (zool.}. 



protomonostelic (pro'to mon'ostel'ik) 

 a. \Gk. protos, first ; monos, alone ; 

 stele, column.] Appl. a stem or 

 root with a protostele or central 

 cylinder (bot.}. 



protonema (pro'tone'ma) n. [Gk. 

 protos, first ; nema, thread.] The 

 germination structure of Mosses, 

 from which the moss plant buds 

 (hot.}. 



protonematoid (pro'tonem atoid) a. 

 [Gk. protos, first ; nema, thread ; 

 eidos, form.] Like a protonema 

 (bot.}. 



protonephridial (pro'tonefrid'ial) a. 

 [Gk. protos, first ; nephros, kidney.] 

 Appl. the excretory water-vascular 

 system of Flat-worms (zool.}. 



protopepsia (pro'to pep'sia) n. [Gk. 

 protos, first ; pepsis, a digesting.] 

 Solution and alteration of food- 

 material accomplished in the di- 

 gestive tract (phys.}. 



protophloem (pro'toflo'em) n. [Gk. 

 protos, first ; phloios, tree-bark.] 

 The first phloem elements of a 

 vascular bundle (dot."). 



protophyte (pro'tofit) n. [Gk. protos, 

 first ; phyton, plant.] A unicellular 

 vegetable organism or primitive 

 plant (bot.}. 



protoplasm (pro'toplazm) n. [Gk. 

 protos, first ; plasma, form.] Cell 

 substance ; cytoplasm and karyo- 

 plasm (cyt.}. 



protoplasmic (pro'toplaz'mik) a. [Gk. 

 protos, first ; plasma, form.] Pert. 

 or consisting of protoplasm (biol.}. 



protoplast (pro'toplast) n. \Gk.protos, 

 first ; plastos, formed.] An energid ; 

 a living uninucleate primitive pro- 

 toplasmic unit (biol.}. 



protopodite (protop'odit) n. [Gk. 

 protos, first ; pous, foot.] The 

 basal segment of a typical crus- 

 tacean limb (zool.}. 



protospore (pro'tospor) n. [Gk. protos, 

 first ; sporos, seed.] A spore of 

 the first generation ; a mycelium- 

 producing spore (hot.}. 



protostele (pro'tostel) n. [Gk. protos, 

 first ; stele, column.] The concentric 



bundle or central cylinder of vascu- 

 lar tissue of most roots and some 

 stems (hot.}. 



prototheca (pro'tothe'ka) n. [Gk. 

 protos, first ; theke, box.] A skeletal 

 cup-shaped plate at the aboral end 

 of a coral embryo, the first skeletal 

 formation (zool.}. 



prototroch (pro'totrok) n. [Gk. protos, 

 first ; trochos, wheel.] A pre-oral 

 circlet of cilia of a trochosphere or 

 trochelminth larva (zool.}. 



prototrophic (pro'totrof'ik) a. [Gk. 

 protos, first ; trophe, nourishment.] 

 Nourished from one supply or in 

 one manner only : appl. bacteria 

 (biol.}. 



prototype (pro'totip) n. [Gk. protos, 

 first ; typos, model] An original 

 type species or example ; an an- 

 cestral form (biol.}. 



protovertebrae (pro'to veVtSbre) n. plu. 

 [Gk. protos, first ; L. vertebra, a 

 vertebra.] A series of primitive 

 segments in a vertebrate embryo, 

 once thought to be the beginnings 

 of vertebrae (emb.}. 



protoxylem (pro'tb'zl'lem) n. [Gk. 

 protos, first ; xylon, wood.] Primary 

 xylem lying next the pith of stems 

 (bot.}. 



protozoaea (pro'tozo'ea) n. [Gk. protos, 

 first ; zoon, animal.] A stage in 

 the life-history of certain Arthropods 

 succeeding the free -swimming 

 nauplius (zool.}. 



protozoology (pro'tozool'ojl) n. [Gk. 

 protos, first ; zoon, animal ; logos, 

 discourse.] The department of 

 Zoology dealing with the simplest 

 animal organisms. 



protozoon (pro'tozo'on) n. [Gk.protos, 

 first ; zoon, animal.] A unicellular 

 animal organism (zool.}. 



protractor (protrak'tor) n. [L. pro, 

 forth ; tractus, drawn out.] A 

 muscle which draws out or extends 

 a part (anat.}. 



protriaene (pro'trlen) n. [Gk. pro, 

 before ; triaina, trident.] A triaene 

 with anteriorly-directed branches 

 (zool.}. 



proventriculus (pro'ventrik'ulus) n. 

 [L. pro, before ; ventriculus, a small 

 stomach.] In Insects, the digestive 

 chamber anterior to the stomach ; 

 in Worms, that anterior to the 



