MEM- 



181 



MER- 



ties by perilymph, and itself con- 

 taining endolymph (ana/.). 



membranous vertebral column, 

 a continuous sheath of mesoderm, 

 enveloping notochord and neural 

 tube (emb.}. 



membranula (me'mbran'ula) n, [L. 

 dim. of membrana, membrane.] A 

 concrescence of cilia, as in certain 

 Infusoria (zoo/.). 



membranule (mgm'branul) n. [L. 

 dim. of membrana, membrane.] A 

 small opaque space, in some 

 dragon-flies' wings, lying close to 

 the body of the insect in the anal 

 area of the wing (zoo/.). 



Mendellan, pert, law, factor or 

 character which behaves accord- 

 ing to the results of Mendel's 

 experiments. 



Mendellsm, a law or rule governing 

 the inheritance of characters in 

 plants and animals discovered by 

 Gregor Mendel. This principle 

 deals with the inheritance of " unit 

 characters," the presence or ab- 

 sence of one or other of a pair of 

 contrasting characters. It also 

 shows that the offspring of organ- 

 isms with a pair of contrasting 

 characters will be produced in a 

 definite ratio. From this law we 

 are able to get a more correct and 

 scientific definition of "purity of 

 a breed." It may be extended to 

 deal with groups of characters. 



meningeal (mgn'Inje'al, mgnm'jeal) a. 

 [Gk., meninx, a membrane.] Pert. 

 or in the region of the meninges ; 

 appl. artery, vein, nerve (ana/.). 



meninges (me'nin'jez) n. plu. [Gk. 

 meninx, a membrane.] The three 

 membranes enclosing the brain and 

 spinal cord, from without inwards 

 the dura mater, arachnoid and pia 

 mater (anat.}. 



meningosis (mgn'ingo'sis) n. [Gk. 

 meninx, a membrane.] Attach- 

 ment by means of membranes. 



meningo-spinal (mening'go-spl'nal) a. 

 [Gk. meninx, a membrane ; L. 

 spina, spine.] Pert, the spinal 

 cord membranes (anat.}. 



meniscus (mgnis'kus) n., menisci 

 (mgnts'kl) plu. [Gk. meniskos, a 

 little moon.] Interarticular fibro- 

 cartilages found in joints exposed 



to violent concussion, such as wrist 

 and knee joints (anat.}. 



mensa (m&n'sa) n. [L. mensa, a 

 table.] The chewing surface of a 

 tooth. 



menstruation (men'strooa'shun) . 

 [L. mensis, a month ; struere, to 

 flow.] A monthly discharge from 

 the female reproductive organs, 

 chiefly in higher mammals (zoo/.). 



mental (mgn'tal) a. [L. mentum, 

 chin.] Pert, or in the region of 

 the chin ; appl. foramen, nerve, 

 spines, tubercle, muscle (anat.} ; 

 pert, the mentum of insects ; apj>L 

 scale or plate of fish and of reptile 

 (anat.}. 



mentigerous (me'ntij'e'rus) a. [L. 

 mentum, chin ; gerere, to carry.] 

 Supporting or bearing the mentum 

 (zoo/.). 



mentomeckelian (me'n'tome'ke'lian) a. 

 [L. mentum, chin ; Ger. Meckel, 

 comparative anatomist.] Appl. a 

 cartilage bone present in a few 

 lower vertebrates at either side of 

 the union of the two halves of the 

 lower jaw (zoo/.). 



mentum (mgn'tum) n. [L. mentum, 

 chin.] The chin (anat.} ; an un- 

 divided mouth-part of Insects, con- 

 tinuous with submentum or gula 

 and posterior to labial palps and 

 palpigers ; a projection between 

 the head and foot of some Gastro- 

 pods (zoo/.). 



mericarp (meYikarp) n. [Gk. meros, 

 part ; karpos, fruit.] A one-seeded 

 indehiscent part of a schizocarp 

 (**} 



meridional canal, in Ctenophores, a 

 canal extending upwards and down- 

 wards beneath a swimming-plate, 

 into which the adradial canals 

 open (zoo/.). 



merism (meYizm) n. [Gk. meros, 

 part.] "A repetition of homo- 

 logous parts." 



merismatic (meYfzmat'ik) a. [Gk. 

 merismos, a partition.] Dividing 

 or separating into cells or seg- 

 ments ; consisting of meristem, as 

 merismatic tissue (oof.). 



merismoid (mgrlz'moid) a. Gk. 

 merismos, partition ; eidos, like.] 

 With branched pileus (bot.\ 



merispore (mgrfspor) n. [Gk. meros, 



