A DICTIONARY OF 



SCIENTIFIC TERMS 



ABA- 



abactinal (abak'tinal, abakti'nal) a. 

 [L. ab, from ; Gk. aktis, ray.] 

 Appl. the area of an echinoderm 

 body without tube-feet and in which 

 the madreporite is usually included ; 

 abambulacral ; antambulacral ; opp. 

 actinal (zoo/.). 



abambulacral (ab'ambula'kral) a. [L. 

 ab t from ; ambulare, to walk.] 

 Appl. the area of an echinoderm 

 body remote from that on which 

 the tube-feet are found (zoo/.). 



abaxial (abak'slal) a. [L. ab, from ; 

 axis, axle.] Pert, that surface of 

 any structure which is remote or 

 turned away from the axis (biol.). 



abaxile (abak'sil) a. [L. ab, from ; 

 axis, axle.] Appl. an embryo in 

 which the axis has not the same 

 direction as the axis of the seed 

 (dot.}. 



abbreviated (abre'vlated) a. [L. ad, 

 to ; brevis, short.] Shortened ; 

 curtailed. 



abdomen (abdo'men, ab'domen) n. 

 [L. abdomen, belly.] The belly ; in 

 vertebrates, the part of the body 

 containing the digestive organs ; in 

 Arthropods and certain Polychaets, 

 the posterior part of the body ; in 

 Synascidians, part of the zooid 

 below the thorax (zoo/., anat.). 



abdominal (abdom'Inal) a. [L. ab- 

 domen, belly.] Pert, abdomen ; 

 appl. structures, organs, or parts of 

 organs situated in, on, or closely 

 related to, the abdomen. 



abdominal pores, single or paired 

 openings leading from the coelom 

 to the exterior, in Cyclostomes and 

 certain other fishes (zoo/.). 



abdominal reflex, contraction of ab- 

 dominal wall muscles when the skin 

 over the side of the abdomen is 

 stimulated (phys.). 



abdominal regions, nine areas into 

 which the abdomen is divided by 



ABO- 



two horizontal and two vertical 

 imaginary lines, viz., hypochondriac 

 (2), lumbar (2), inguinal (2), epigas- 

 tric, umbilical, hyppgastric (anat.). 



abdominal ribs, ossifications occur- 

 ring in the fibrous tissue between 

 skin and muscles of certain reptiles 

 (zoo/.). 



abdominal ring, one of two openings 

 in the fasciae of the abdominal 

 muscles through which passes the 

 spermatic cord in the male, and the 

 round ligament in the female ; 

 inguinal ring (anat.}. 



abducens (abdu'se'nz) n. [L. abducere, 

 to lead away.] The sixth cranial 

 nerve supplying the rectus externus 

 which turns the eyeball outwards 

 (anat.). 



abduct (abdukt') v. [L. abducere, to 

 lead away.] To draw away from 

 the median axis (phys.}. 



abductor (abduk'tor) n. [L. abducere, 

 to lead away.] A muscle that 

 draws a limb or part outwards 

 (anat.). 



aberrant (abeYant) a. [L. aberare, to 

 wander away.] Appl. species with 

 characteristics not strictly in accord- 

 ance with the type (bot., zoo/.). 



abiogenesis (abiqje'n'gsis) n. [Gk. a, 

 not ; bios, life ; genesis, birth.] The 

 production of living from non-living 

 matter ; archegony ; autogony ; 

 spontaneous generation (oio/.). 



abiology (ablol'oji) n. [Gk. a, not ; 

 bios, life ; logos, discourse.] The 

 study of non-living things ; anor- 

 ganology. 



abomasum (aboma'zum, abom'azum) 

 n. [L. ab, from ; omasum, paunch.] 

 The read or fourth chamber of the 

 stomach of ruminants (zoo/.). 



aboral (abo'ral) a. [L. ab, from ; os, 

 oris, mouth.] Away from, or 

 opposite to, the mouth. 



abort (abort') v. [L. abortus, prc- 



