ASC- 



24 



ATR- 



askos, bag ; gignesthai, to produce.] 

 A sac-like structure in which the 

 reproductive bodies are formed 

 (bot.). 



ascospore (as'kospor) n. [Gk. askos, 

 bag ; sporos, seed.] One of the 

 spores contained in an ascus (bot.). 



ascus, sing, of asci, which see. 



asexual (aseVsual) a. [Gk. a, with- 

 out ; L. sexus, sex.] Having no 

 apparent sexual organs ; patheno- 

 genetic or vegetative as appL repro- 

 duction (btol.). 



aspect (as'pekt) n. [L. ad, to; 

 spectare, to look.] Look, appear- 

 ance, point of view (btol.). 



asperity (aspeViti) n. [L. asper, 

 rough.] Roughness as on certain 

 leaves (hot.}. 



aspidobranchiate (as'pidobrang'kiat) 

 a. [Gk. aspis, shield ; brangchia, 

 gills.] Pert, or resembling the 

 Aspidobranchiata, a group of 

 Gasteropods (zool.). 



asplanchnic (asplangk'nik) a. [Gk. 

 a, without ; splangchna, viscera.] 

 Without alimentary canal (zool.). 



asporous (asp5'rus) a. [Gk. a, with- 

 out ; sporos, seed.] Having no 

 spores (bot.). 



assimilation (asTm'ila'shun) n. [L. ad, 

 to ; similis, like.] Conversion into 

 protoplasm of ingested nutrient 

 material (phys.). 



association (aso'sia'shun) . [L. ad, 

 to ; socius, fellow.] Adherence of 

 gregarines without fusion of nuclei 

 (zool.} ; appl. fibres connecting 

 white matter of interior of brain 

 with cortex of convolutions (phys.). 



astely (Aste'H) n. [Gk. a, without ; 

 stele, pillar.] Absence of a central 

 cylinder or axis (hot.}. 



aster (as'tgr) n. [Gk. aster, a star.] 

 The star-shaped achromatinic 

 structure surrounding the centro- 

 some during mitosis ; the star- 

 shaped arrangement of the 

 chromosomes during mitosis (cyt.). 



asterion (aste'rion) n. [Gk. aster, 

 star.] The region of the postero- 

 lateral fontaneTle where lambdoid, 

 parieto - mastoid, and occipito- 

 mastoid sutures meet (anat.). 



asteroid (as'tgroid) a. [Gk. aster, star ; 

 eidos, resemblance.] Star-shaped ; 

 pertaining to the star-fish (zoou). 



asterospondylous (as'tSrospon'dllus) 

 a. [Gk. aster, star ; sphondylos, 

 vertebra.] Having centrum with 

 radiating calcified plates (zool.). 



astomatous (astom'atus) a. [Gk. a, 

 without; stoma, mouth.] Not having 

 a mouth (zool.) ; without epidermic 

 pores or stomata (bot.). 



astomous (asto'mus) a. [Gk. a, with- 

 out ; stoma, mouth.] Without a 

 stomium or line of dehiscence ; 

 bursting irregularly (bot.). 



astragalus (astrag'alus) n. [Gk. 

 astragalos, an ankle bone.] The 

 second largest tarsal bone in man 

 (anat.); a tarsal bone in Vertebrates. 



astrocentre (as'trosSn'ter) n. [L. aster, 

 star ; centrum, centre.] The centro- 

 some (cyt.). 



astrosphere (as'trosfer) n. [Gk. aster, 

 star ; sphaira, ball.] The central 

 mass of the aster without the rays ; 

 the aster exclusive of the centro- 

 some ; the astral sphere (cyt.). 



asymmetrical (asimet'rikal) a. [Gk. 

 a, without ; syn, with ; metron, 

 measure.] Pert, want of sym- 

 metry ; in the condition of having 

 two sides unlike or disproportion- 

 ate ; appl. structures or organs 

 which cannot be divided into 

 similar halves by any vertical axis 

 (biol.\ 



asymmetry (asTm'gtri) n. [Gk. a, with- 

 out ; syn, with; metron, measure.] 

 Want of symmetry. 



atavism (at'avizm) n. [L. atavus, 

 ancestor.] Reversion, the oc- 

 currence of a characteristic of a 

 remote ancestor not .observed in 

 the more immediate ancestors 

 (btol.). 



atavistic (at'avls'tik) a. [L. atavus, 

 ancestor.] Pert, marked by, or 

 tending to atavism (btol.). 



athalamous (athal'amus) a. [Gk. a, 

 without ; thalamos, inner room.] 

 Wanting a thalamus (bot.). 



atlas (at'las) n. [Gk. atlas, a giant.] 

 The first cervical vertebra articulat- 

 ing with the skull (anat.). 



atokous (at'okus) a. [Gk. atokos, 

 childless.] Without offspring. 



atoll (at'61, atol') n. [Mai. atoll.} A 

 coral reef surrounding a body of 

 water (zool.). 



atria! (a'triil) a. [L. atrium, a central 



