寻常海绵纲
- 网络Demospongiae;demosponge;class demospongiae;Demopongiae;DenIospongiae
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虽然现在所发现的海绵中约有90%都属于寻常海绵纲,但此类海绵化石比其他类型的更加罕见,因为它们的骨骼由相对柔软的海绵硬蛋白组成,不易形成化石。3.水母
Although about 90 % of modern sponges are demosponges , fossilized remains of this type are less common than other types because their skeletons are composed of relatively soft spongin that does not fossilize well . 3.Jellyfish