Then followed a subsidence, which not only re-established communication through the Danish channels, but allowed the Baltic to become sufficiently salt for such forms as Cardium edule and Littorina littorea.
A, Arrow from proboscis-cavity (pc) passing to left of peri cardium (per) and out through proboscis pore-canal.
A very large number of species of Cardium have been distinguished by conchologists.
In the cockles, in Cardium and in Trigonia, it is capable of a sudden stroke, which causes the animal to jump when out of the water, in the latter genus to a FIG.
Other marine forms are Rhizopoda (Rotalia and Textillaria), the sponge Amorphina, the Amphicteis worm, the molluscs Cardium edule and other Cardidae, and some Amphipods (Cumacea and Mysidae,), but they are forms which either tolerate variations in salinity or are especially characteristic of brackish waters.
Grimmi), Cardium ponticum (to C. caspium), C. coloratum (to Monodacna edentula), Amphicteis antiqua (to A.
Besides the common species Cardium edule, two others occur in Britain, but are not sufficiently common to be of commercial importance.
The depths of the Black Sea are lifeless, higher organic life not being known to exist below loo fathoms. Fossiliferous remains of Dreissena, Cardium and other molluscs have, however, been dredged up, which help to show that conditions formerly existed in the Black Sea similar to those that exist at the present day in the Caspian Sea.