Page:Natural History, Mollusca.djvu/69
mere trinkets on which he looked dotingly, without knowing, and scarcely wishing to know, the organization of the animal whose skeleton only was before him."
In these days, however, the examination of the shell is considered by all who possess any claim to science, as subordinate to the history of the entire animal.
Naturalists arrange the Mollusca in six classes, named Cephalopoda, Pteropoda, Gasteropoda, Conchifera, Brachiopoda, and Tunicata. Of these the first three are sometimes distinguished as Encephala, or furnished with a head; the last three as Acephala, being destitute of that organ.