Freeman Bibliographical Database
| Identifier: | A6993 |
| Date: | 1873 |
| Concise reference: | Haeckel, Ernst. 1873. On the Calcispongiæ, their position in the animal kingdom, and their relation to the theory of descendence. Annals and Magazine of Natural History 4th ser. 12 no. 71: 421-430. [CUL-DAR.LIB.PER-U350] |