Meanings of invertebrate ancestors in English

The whole of the invertebrate ancestors of the human race must have preceded these.

But we find these lower stages in their original purity in the lower vertebrates and their invertebrate ancestors.

All man's earlier invertebrate ancestors, from the Gastræads up to the Prochordonia, were hermaphrodites; possibly even the earliest Acrania.

These were very great in the series of our invertebrate ancestors; they are much slighter in the subsequent series of our vertebrate ancestors.

Their invertebrate ancestors were soft organisms without skeleton, and thus incapable of fossilisation, as is still the case with the lowest vertebrates-theAcrania and Cyclostoma.