种壳 meaning in English

testa

In addition , to these three characteristics , there are also two other shell characters , shell thickness and shell smoothness , which are not easily studied by quantitative analysis
除这三种壳因子外，还有两个难以定量比较分析的贝壳形态特征，即壳厚度或坚硬度和光滑度。
The results of factor analysis showed that the following three shell factors are independent , and that there are no correlations among them : shell size , shell flatness and protoconch whorl number
因子分析结果显示壳大小、壳扁度及原壳螺层数三种壳因子是相互独立的，它们之变异互不相关。