海绵动物是多细胞动物中最原始的类型,最早对海绵动物的了解来自于现代海洋中的活标本,它们曾和一些海洋多射型无脊椎动物一起被列入辐射动物门,也曾归于腔肠动物,被列入独立的一个动物门已有百余年。因为是低等多细胞动物,几乎各种生物学教科书中都把海绵动物门排在多细胞动物最前面的章节来叙述。海绵动物不是衰退的类群,目前已经发现的 Sponge is the most primitive type of multicellular animals. The earliest understanding of sponges came from living specimens in modern oceans. They were included in radiation animal gates along with some marine pollinating invertebrates and also belong to the cavity Intestine, has been included in an independent animal door more than a hundred years. Because it is a low-grade multicellular animal, almost all sorts of biology textbooks place the sponge door in the forefront of multicellular animals. Sponge is not a recession group, has now been found