374 APPENDIX III 



METAPLEURAL (G. meta, plus pleura, side), specifically the folds of tissue 

 along the sides of Amphioxus; metapleural folds. 



MINIMUS (G. least), used as a limiting adjective. 



MINOR (L. less), descriptive adjective; as pectoralis minor or p. major. 



Miocene (G. meion, less, plus kainos, recent), a geological period of 

 Tertiary (Cenozoic) times, between the Oligocene and Pliocene. 



MississiPPiAN (from Mississippi Valley where it was first described), a 

 period of late Paleozoic time; the lower strata of the rocks formerly 

 included as the Carboniferous Period. 



MITRAL (G. mitra, a turban; a divided bishop's hat), relating to the 

 bicuspid valves in the left auriculo-ventricular opening of the mam- 

 malian heart. 



MOLAR (L. molaris, belonging to a mill), the posterior, permanent, teeth 

 of a mammal. 



MONO (G. single), a combining form. 



MoNOTREMATA (G. moiio, single, plus tremato, an opening), a sub-class of 

 mammals from Australasia; egg laying mammals with a cloaca, or 

 single opening for the anus and urinogenital outlets. 



MORPH (G. morphe, form), a combining word. 



MORPHOLOGY (G. morphe) , the study of structure or form; more fre- 

 quently u^ed in the sense of developmental anatomy. 



MuLLERiAN (from Miiller, a German anatomist, 1801-1858), specifically 

 the Miillerian ducts of the mammal embryo which give rise to the 

 uteri; same as oviduct. 



MusTELUS (L. mustela, weasel), a genus of sharks; the smooth dogfish. 



MYELON (G. marrow), a combining form referring to marrow or a marrow- 

 like substance; the myelin sheath of neurones; myelocytes. 



MYo (G. mys, muscle), a combining form; myology, the study of muscles; 

 myocomma; myotome. 



MYOCOMMA (G. mys, plus komma, a segment), a connective tissue band 

 separating two myotomes. 



MYOTOME (G. mys, plus tomes, a cut), a muscle segment or somite. 



Myxine (G. myxa, slime), a genus of myxinoid cyclostomes. 



Myxinoidea ((^. myxa, plus eidos, like), a sub-class of cyclostomes, in 

 many respects more primitive than the lampreys; the "sHmy eels". 



MYzoN (G. sucker), a combining form; Petromyzon, the lamprey or 

 "stone sucker". 



NARis (L. nostril), singular of nares; the opening of the air passages, both 



internal and external. 

 Neanderthal (a valley in Prussia), an extinct race of man; H. neander- 



thalensis. 

 Necturus (G. nektos, to swim, plus oura, tail), a genus of urodele 



amphibia with external gills throughout life; a typical form in labora- 

 tory dissections. 

 neo (G. neos, new), a combining form referring to recent development. 

 neop.\llium (G. neos, phis palli, a mantle or cover), the cover of the 



cerebral hemispheres which has a cortical region; opposite of archi- 



pallium. 

 NEPHROS (G. kidney), a combining form; mesonephros; nephric tubule. 

 nephrostome (G. nephros, plus stoma, mouth), the ciliated opening of a 



pronephric or mesonephric tubule into the coelomic cavity. 



