ASTEBOIDEA 



35 



ATHERFIELD 



corundum, which, when cut perpendicular 

 to its axis, resembles a star. 



Asteroidea, (as-ter-oi'de-a). [Gk. aster, a star; 

 eidos, form,] A division of Echinodermata, 

 incluidng Ophiuridse and Asteriadse, or sand- 

 stars and star-fishes : pentagonal inverte- 

 brate animals, with coriaceous integument. 



Asteroids, (as'ter-oidz). [Gk. aster, star; eidos, 

 form.] 1. = Asteroidea, q.v. 2. = Minor 

 planets=Planetoids: small stars, nearly 150 

 in number, varying from 20 to 250 miles in 

 diameter, usually of low magnitude, whose 

 orbits lie between those of Mars and Jupiter: 

 supposed to be fragments of a large planet. 

 These have been discovered at intervals be- 

 tween 1800 and now, and the number is fre- 

 quently increased by new discoveries. 



Asterolepis, (as-ter-ol'e-pis). [Gk. aster, star; 

 lepis, scale.] A very Jarge ganoid fish, re- 

 mains of which are found in Devonian strata, 

 named from the star-like markings on the 

 head. 



Asterophyllites, (as-ter-o-fil'lits). [Gk. aster, 

 star; phyllon, leaf.] Fossil remains of plants, 

 resembling Calamites, and allied to Lyco- 

 pods, the leaves of which are in star-like 

 whorls: common in Coal-measures. 



Asthenia, (a-sthen'i-a). [Gk. a, without; sthen- 

 os, strength.] Weakness. 



Asthenic, (a-sthen'ik). [Asthenia, q.v.] Hav- 

 ing but little strength. 



Asthenopia, (as-then-o'pi-a). [Asthenia, q.v. ; 

 Gk. ops, eye.] Weakness of eyesight. 



Astoma, (a'sto-ma). [Gk. a, without; stoma, 

 mouth.] A sub-division of Infusoria, marked 

 by the absence of any mouth. 



Automatons, (a-stom'a-tus). [Gk. a, without; 

 stoma, mouth. ] = Astornous : having no 

 mouth. 



Astracamite, (as'tra-ka-mit). A white mine- 

 ral, chiefly suluhate of magnesium and 

 sodium. 



Astrsea, (as-tre'a). [Classical.] 1. One of the 

 Asteroids, q.v., No. 5. ' 2=Star-coral: a coral 

 polype, belonging to Aporosa, q.v. 



Astrseidae, (as-trg-i-de). [Astrsea, q.v.]= Star- 

 corals: a family of coral polypes, of which 

 Astrtea is the type. 



Astragal, (as'tra-gal.) [Gk. astragalos, ankle- 

 bone.] A semicircular moulding, forming a 

 kind of ring at the base and top of columns; 

 sometimes cut into beads. 



Astragalus, (as-trag'a-lus.) [Gk. astragalos, 

 ankle bone.] 1. Milk Vetch: herbs and 

 shrubs, some with stems that yield gums, 

 belonging to Fabacese, said to be named from 

 the shape of the seeds. 2. The bone in the 

 ankle by which the foot bears the weight of 

 the body. 



Astralite, (as'tra-lit). A glass flux resembling 

 avanturine. 



Astrea=Astrsea, q.v. 



Astrogeny, (as-troj'e-ni). [Gk. aster, star.]= 

 Astronomy: the laws of the re-distribution 

 of matter and motion among the molecules 

 of celestial masses. 



Astrography, (as-trog'ra-fi). [Gk. aster, star; 

 grapho, I write.] A description of the 

 planets, fixed stars, &c. 



Astrolabe, (as'tro-lab). [Gk. aster, star; to- 

 bein,to take.] Originally 

 used for any instrument 

 used for observing stars; 

 afterwards used for au 

 instrument for meas- 

 urement of altitude: re- 

 placed, in modern prac- 

 tice, by the quadrant. 



Astrology, (as-trol'o-ji). 

 [Gk. aster, star; logos, 

 description.] Properly 

 ^Astronomy, but used Astrolabe, 



only for the pretended science, now almost 

 obsolete, of the influence of the stars upon 

 the fortunes and actions of men. 



Astroraetry, (as-trom'e-tri). [Gk. aster, star; 

 metron, measure.] The measurement of the 

 stars as to their brightness, diameters, &c. 



Astronomy, (as-tron'o-mi). [Gk. aster, star; 

 nomos, law.] The science of the stars and 

 their motions, and the laws governing them. 



Astropecten, (as-tro-pek'ten). An animal be- 

 longing to Asteridea, which has no swim- 

 ming organs, and is found only at the sea- 

 bottom ; found fossil in London Clay. 



Astrophyllite, (as-tro-fil'lit). [Gk. aster, star 

 phyllon, leaf.] A variety of mica, contain- 

 ing more iron than usual: named from the 

 crystals being often in star-like groups. A. 

 crispatus. 



Astroscopy, (as-trosTco-pi). [Gk. aster, star 

 skopeo, I observe.] Observation of the stars. 



Asymmetry, (a-sim'met-ri). [Gk. ajiymmetros, 

 disproportionate.] Not symmetrical. 



Asymptote, (a-simp'tot). [Gk. a, not; syn, 

 with; ptosis, fall ]=A.sym tote: a line which 

 continually approaches a curved line with- 

 out ever actually touching it. 



Asyzgetic, (a-siz'jet-ik). A system not in in- 

 volution. A mathematical term. 



Atacamite, ( at'a-ka-mit ). [From Atacama, 

 Peru.]=Native cupric oxychloride=Copper- 

 sand, found in Chili and Australia. 



Atalanta, (at-a-lau'ta). One of the Asteroids, 

 q.v., No. 36. 



Atavism, (a'ta-vism). [L. atavus, ancestor.. 

 The tendency of offspring to closely resemble 

 their parents: one of the causes of species. 



Ataxic, a-taks'ik). [Gk. a, not; tasso, I ar- 

 range.] Irregular; not in order. Cf. Taxo- 

 nomy. 



Ateles, (a'te-lez.] [Gk. ateles, imperfect.]= 

 Spider-monkeys : American monkeys, with 

 long, slender limbs and prehensile tails, liv- 

 ing in trees, and having no thumb, forming 

 a division of Simia. A. paniscus=Qna.ta. 

 Coaita. A. marginatus=Clmvo. A. ater, 

 Cayou. A. 6eZsc6w6=Marimonda. A. hypo- 

 xanthus = Mono. A. subpentadactylus = 

 Chameck. 



Athabasca, (ath-a-baslca). An American race. 



Athamantin, (a-tha-man'tin). C 2 4H 30 O7 : a 

 fibrous crystalline substance obtained from 

 several species of the Athamanta plant. 



Athar= Attar, q.v. 



Atherfield clay. [Atherfield, in Isle of Wight.] 

 A marine sub-division of Upper Neocomian 

 rockg. 



