In a pennaceous feather, the barbs grow helically around the tubular feather germ and fuse on one side to form the rachis.Simultaneously, new barb ridges form on the other side of the tube.
正上,枝以螺旋状的芽生长,的一侧接合一起成轴,同时的另一侧成新的枝脊。
声明:以上例句、词性分类均由互联网资源自动生成,部分未经过人工审核,其表达内容亦不代表本软件的观点;若发现问题,欢迎向我们指正。