Crania synonyms

In Crania, where only indications of the lip-sinus occur, there are two other closed spaces.

The above account applies more particularly to Crania, but in the main it is applicable to the other Inarticulata which have been investigated.

Other common genera are Spirifer, Chonetes, Athyris, Rhynchonellids and Terebratulids, Discina and Crania.

Other forms show no indication of ever having been attached, while some that had been moored by means of a peduncle during the early portion of their existence have become detached at a more advanced stage of life, the opening becoming gradually cicatrized, as is so often seen in Leptaena rhomboidalis, Orthisina anomala, &c. Lastly, some species adhere to submarine objects by a larger or smaller portion of their ventral valve, as is the case with many forms of Crania, Thecidium, Davidsonia, &c. Some Cranias are always attached by the whole surface of their lower or ventral valve, which models itself and fills up all the projections or depressions existing on either the rock, shell or coral to which it adhered.

His most important anthropological work was his description of sixty human crania published originally in fasciculi under the title Collectionis suae craniorum diversarum gentium illustratae decades (Gottingen, 1790-1828).