ACA 



iated siliceous spines : Acanth- 

 opterygii, n. plu., dKdnih'tip'tr- 



idj'i-i (Gr. pterugion, a winglet 

 or fin from pterux, a wing), a 

 group of bony fishes with the 

 spinous rays in the front of the 

 dorsal fin. 



Acarina, n. plu., ak'-ar>in'a (L. 

 acarus, Gr. akari, a mite), a 

 division of the Arachnida of 

 which the cheese mite is the type : 

 acaroid, a., ak'-ar-oyd (Gr. eidos, 

 resemblance), resembling the ac- 

 arus or louse : Acarus, n. , ak'ar-us 

 (L.), a genus of insects which in- 

 fest the skin : Acari, n. plu. , akf- 

 ar-i; Acaridse, n. plu., ak-ar'-id-e, 

 the systematic name for such in- 

 sects as the mite, the tick, the 

 water mite, etc. 



acaulis, a., ak-awl'is, acaulous, 

 a., ak-awl'-us, and acauline, a., 

 ak'dwl'-m (Gr. a, without; Gr. 

 Jcaulos, L. caulis, a stalk), with- 

 out a stalk ; steuiless : acaules- 

 cent, a., aktdwl'Zs'ent, having a 

 shortened stem; denoting the 

 non-development of the growing 

 axis : acaulosia, n. , ak'a/wl-dz'i-a, 

 the non-development of the stem 

 of a plant. 



accelerator, n., ak-sel'-er-at'-or (L. 

 accelero, I hasten forward from 

 ad, to ; celero, I hasten, celer, 

 swift), a hastener forward ; that 

 which causes to move faster : 

 accelerator urinse, ur-ln'-e (L. 

 accelerator, a hastener ; urina, 

 urine, urince, of urine), the acceler- 

 ator of urine ; a muscle of the 

 penis whose action propels the 

 urine ; when it does the same for 

 the semen, it is called the ejacul- 

 ator seminis. 



accessorius, n., ak-ses-sor'-i-us (L. 

 accessus, a coming to, an approach 

 from ad, to ; cessum, to go), 

 denoting any muscular append- 

 age which assists the action 

 of a larger muscle ; denoting 

 two nerves of the neck: ac- 

 cessorius ad sacro-lumbalem, 

 ad sdk'-ro lum-bdl'Zm (L. 



t AGO 



ad, to; sacro, sacred; lumbalem, 

 accus., lumbalis, nom., pert, 

 to the lumbus or loin), de- 

 noting the muscle which acts as 

 an assistant to the sacro-lumbalis, 

 consisting of muscular slips which 

 pass from the lower six to the 

 upper six ribs, near their angles : 

 accessorius obturatorii, oV>tur- 

 at-or'-i'l (L. obturator, a stopper 

 up of a cavity, obturatorius, 

 pert, to the stopper up of 

 a cavity, obturatorii, gen. 

 from obt&ro, I stop up), the 

 accessory or assistant of the ob- 

 turator applied to a muscle or 

 nerve which assists, or is an 

 appendage to, the obturator : 

 accessorius pedis, p%d f -is(L. pes, a 

 foot, p%dis, of a foot), an accessory 

 muscle of the foot, arising from 

 the under surface of the os calcis 

 by two heads, and assists to bring 

 the line of traction of the flexor 

 tendons into the centre of the 

 foot. 



accouchement, n., ak-kdosh'mong 

 (F. accoucher, to deliver from 

 coucher, to lay down ; L. ad, 

 to; colloco, I lay in a place), 

 lying in child-birth ; the act 

 of parturition : accoucheur, n. , 

 d&koosh-er' ', a surgeon who at- 

 tends women in child-birth ; a 

 man -midwife ; an obstetrician : 

 accoucheuse, n., ak'-kobsli-dz' , a 

 female who practises midwifery ; 

 a midwife. 



accrescent, a., ak-lcres'^nt (L. ad, 

 to ; crescens, growing), denoting 

 plants continuing to grow and 

 increase after flowering. 



accrete, a. , ak-lcreif (L. ad, to; cret- 

 um, to grow), grown together : 

 accretion, n. , aTc-kresh'-un, the act" 

 of growing by increase ; growth 

 by external addition to new 

 matter ; in surg. , the conjunc- 

 tion of parts naturally separate. 



accumbent, a., ak-kumb-ent (L. 

 accumbens, lying on from ad, 

 to or on ; cubo, I lie down), 

 lying on ; supine ; prostrate ; in 



