Definition:中央孔zhōng yāng kǒng在颗石的中央区,大部分类型有一个空洞。central: in,near,or forming the middle of something中心的zhōng xīn deopening: vacancy空缺kòng quē...[继续阅读]

    Definition:An order of extinct fishes in the class acanthodii having scales of acellular boneand dentine,one dorsal fin,and no teeth.棘鱼目jí yú mù棘鱼类中最晚出现并最晚灭绝的种类,早泥盆世至早二叠世。没有牙齿或肩带腹面的膜质板,仅具一个背鳍,具棘鱼型...[继续阅读]

    Definition:The common name for four extinct classes of primitive echinoderms that have aflattened theca or body lacking radial symmetry. These enigmatic fossils were originallyclassified together in the class Carpoidea,but more recent echinoderm researche...[继续阅读]

    Definition:Any of a group (genus Aepyornis or order Aepyornithiformes)of giganticflightless ratite birds known only from remains found in Madagascar.象鸟 xiàng niǎo 生活于马达加斯加第四纪的巨型植食性平胸鸟类,翼退化,无飞行能力。至少在16世纪以前已灭绝。Origi...[继续阅读]

    Definition:The midsection of a long bone;diaphysis.锚干máo gàn锚形骨片的组成部分,指锚臂与柄端之间的干状部分。Origin:From Old English sceaft....[继续阅读]

    Definition:一级隔壁yī jí gé bì发生在次级隔膜内腔中的隔壁,常与原生隔壁等长。major: greater than others in importance or rank主要的z hǔ yào deseptum: a thin partition or membrane that divides two cavities or soft masses of tissue in anorganism隔壁gé bì...[继续阅读]

    Definition: In population genetics,the founder effect is the loss of genetic variation thatoccurs when a new population is established by a very small number of individuals from a largerpopulation. It was first fully outlined by Ernst Mayr in 1952,using e...[继续阅读]

    Definition:The vein which often has cross-connections that form closed “cells”in themembrane.纵脉zòng mài从翅基部伸向翅边缘的脉。...[继续阅读]

    Definition:侧部cè bù中间板表面的部分,在两侧呈三角形。lateral:situated on one side or other of the body or of an organ,especially in the region furthestfrom the median plane外侧的wài cè deExample:Cheek is the whole of the lateral area below and posterior to the eyes on each si...[继续阅读]

    Definition:Having a single whorl,as certain flowers and the shells of certain invertebrates.单环式dān huán shìOrigin:International Scientific VocabularyExample:This toxin is a class of monocyclic heptapeptides with many different isomerides.该毒素是一类具有多种异构体的环状多...[继续阅读]