ACRODONTA 



8 



ADIANTTTM 



Acrodonta, (ak-ro-dont'a). [Acrodont teeth, 

 q.v.] Iguanas, of the old world, having teeth 

 fixed on the ridge of the jaw. 



Acrodont teeth, (ak'ro-dont). [Gk. akros, high; 

 odous, tooth.] Teeth fixed on the upper ridge 

 of the jaw, and not in cavities, as in some 

 lizards. 



Acrodus, (ak'ro-dus). A placoid fish, known 

 only by fossil teeth, found in lias rocks. 



Acrogeneae, (ak-rO-jen'e-e). [Acrogens, q.v.] 

 Acrogens. 



Acrogens, (ak'ro-jenz). [Gk. akros, high; 

 gennao, I produce. ] Mosses, ferns, &c.; 

 plants of cellular tissue, growing in length 

 only, having no flowers or seed-leaves. Also 

 used as equivalent to acotyledons. 



Acrognathus, (ak-rog-nath'us). [Gk. akros, 

 high ; gnathos, jaw-bone.] A fish of the 

 salmon kind, known only by fossil remains 

 found in chalk rocks. 



Acrolein, (ak-ro'lm). [L. acer, sharp; Oleic, 

 q.v.] Acrylic aldehyd=C3H 4 O: a colourless 

 inflammable neutral liquid obtained from 

 glycerin, acetic bromide, &c. 

 Acromion, (ak-ro'mi-on). [Gk. akros, sum- 

 mit; omos, shoulder.] A projecting portion 

 of the scapula in man. 



Acronical, (a-kron'ik-al). [Gk. akros, point; 

 nux, night.] Rising or setting at the time 

 of sunset. 



Acrpsaurus, ( ak-ro-saw'rus ). [Gk. akros, 

 point; sauroii, lizard.] A fossil reptile, hav- 

 ing its teeth on the edge of the jaw. 



Acrylates, (ak-ri'lats). [Acrylic acid, q.v.] 

 Compounds of bases with acrylic acid. 



Acrylic acid, (a-kri'lik as'id). [Acrolein, 7.1-.] 

 CaH^s, acroleic acid obtained by oxidation 

 of acrolein, an pdorous and acrid liquid, 

 one of the oleio series. 



Actaea, (ak-te'a). [Gk. akte, elder.] Baneberry= 

 Herb Christopher: a poisonous herb, common 

 in cold climates, belongingto Ranunculacese. 



Actiniae, (ak-tin'i-5). [Gk. aktis, a ray.] Sea- 

 anemones, &c., a group of marine animals, 

 belonging to Zoantharia, from in. to 14 in. 

 diameter, usually between in. and 3 in., 

 attached to stones, shells, and rocks; can 

 move, but very slowly. Sometimes found 

 on the back of a crab; some have eyes, with 

 crystalline lenses and optic nerves; also a 

 generally diffused sense of touch. 



Actinic rays, (ak-tin'ik raz). [Gk. aktis, ray 

 (of sunlight).] Rays beyond the violet end 

 of a spectrum, usually invisible, but having 

 strong chemical action = Ritteric rays = 

 Phosphorogenic rays. 



Actinism, (ak'tin-izm). [Gk. aktis, ray.] The 

 power of sunlight to cause chemical action, 

 as in photography. 



Actinocarpus, (ak-tin-o-kar'pus). [Gk. aktis, 

 ray; karpos, fruit.] Star fruit: a group of 

 aquatic plants belonging to Alismaceaa. 



Actinocrinites, (ak-tin-ok'ri-nlts). [Gk. aktis, 

 ray; krinon, lily.] A group of encriuites 

 having projecting spines, found in Carboni- 

 ferous and Silurian strata. 



Actinoids, (ak'tin-oidz). [Actiniae, q.v.} Ac- 

 tinisw, and other animals of the same kind, 

 as metridium, &c., some are coral making. 



Actinolite, ( ak-tin'o-lit ). [Gk. aktis, ray; 

 lithos, stone.] A mineral of the amphibolo 

 group. 



Actinolite-schist, (ak-tin'o-lit-shist). [Actin- 

 olite, q.v.] A slaty rock, chiefly composed of 

 actinolite, in thorn-like or radiating crystals. 



Actinophrys, (ak-tin'o-fris). [Gk. aktis, ray; 

 ophrys, eyebrow.] Protozoa, with radiating 

 cilia, any part of the surface of which is 

 capable of terming a temporary stomach. 



Actinosoma, ( ak-tin-o-so'ma ). [Gk. aktis, 

 ray; soma, body.] The entire body of an 

 actinozoon, whether single or compound. 



Actinozoa, (ak-tin-o-zo'a). [Gk. aktis, ray; 

 zoon, animal.] Zoophyta=Anthozoa=Coral- 

 pplypes, Sea-anemonaa, &c.; forming a sub- 

 division of Coelenterata, and including 

 Ctenophora and Coralligena; their structure 

 resembles that of Hydrozoa, but is some- 

 what more highly organised. 



Actinozoon, (ak-tin-o-zp'on). [Same as Actin- 

 ozoa, q.v.] An individual of the Actinozoa. 



Acyclic, (a-si'klik). [Gk. a, without; kyklos, 

 circle.] Without cycles. 



Adamantine lustre, ( ad-a-mant'm lus'ter). 

 [Gk. adamas, a hard stone.] Found in sub- 

 stances, like the diamond, having a high 

 refractive power. 



Adam's apple, (ad'amz ap'pl). [Name derived 

 from the Fall of Adam and Eve.] A ]>n>- 

 jection in the front of the neck, being the 

 apex of the V-shaped thyroid cartilage. 



Adam's needle, (ad'amz nSd'l). A plant of 

 New Mexico= Yucca gloriosa. 



Adansonia, (ad-an-so'ni-a). [Adanson, a 

 naturalist.] Baobab tree=Calabash: a very 

 large African tree, sometimes 30 ft. in 

 diameter, belonging to Bombaceaa. 



Adder, (ad'er). [A.-S. alter, adder.] Viper; 

 a poisonous serpent. 



Adder's tongue, (ad'erz 

 tung). [From shape of (I 

 fronds]=Ophioglossum: ' 

 a common fern. 



Adelarthrosomata, ( a- j 

 del-ar-thro-so'ma - ta ). 

 [Gk. adelos, hidden ; 

 arthron, joint ; goma, 

 body.] Harvest -spiders, Book-scorpions, 

 &c.: a division of Arachnida, in which the 

 abdomen and thorax are not usually clearly 

 divided. 



Adeniform, (ad-en'i-form). [Gk. aden, gland.] 

 Gland-shaped. 



Adenology, (ad-en-ol'o-ji). [Gk. aden, gland.] 

 The knowledge of the nature and purpose 

 of glands. 



Adfected, ( ad-fek'ted ). [L. ad, to ; factus, 

 made.] An adfected equation is one having 

 the unknown quantity in different powers, 

 as yfl and x, x* and #3, <fec. 



Adhesion, (ad-he'zhun). [L. ad, to; hcero, I 

 stick.] The form of molecular attraction 

 which exists between any solid body, and 

 any other body, solid, liquid, or gaseous. 



Adiantites, (adi-an-ti'tez). [Adiautum, q.v.] 

 Fossil remainspf ferns, resembling adiantum. 



Adiantum, (ad-i-ant'um]. [Gk. adiauton, un- 

 wetted.] = Maiden-hair: a fern found in 



Adder. 



