Shell money most valued by the Native American tribes of the Pacific Coast from Alaska to northwest California was "Dentalium shell", a species of long narrow marine shelled mollusk, a tusk shell or scaphopod. The tusk shell is naturally open at both ends, and can easily be strung on a thread. This shell money was valued by its length rather than the exact number of shells; the "ligua", the highest denomination in their currency, was a length of about 6 inches. Farther south, in central California and southern California, the shell of the olive snail "Olivella biplicata" was used to make beads
Shell-less chick embryo culture Shell-less chick embryo culture Shell-less chick embryo culture is the process of growing chick embryos "in vitro", without their protective egg shells, for scientific observation. Chick embryos and other avian embryos have been biological models to visualize the developmental stages of embryos for education and to instigate embryological manipulations. Using this technique, observations can be made, whether it is a induced-malformation caused due to effect of teratogens or the route of viruses inoculations such as HIV or herpes simplex. Furthermore, preservation of endangered avian and development of transgenic birds using surrogate egg shell culture have been contrived by scientists across