Herbert called Pencroft, who ran up hastily.
"Here are mussels!" cried the sailor; "these will do instead of eggs!" "They are not mussels," replied Herbert, who was attentively examining the molluscs attached to the rocks; "they are lithodomes." "Are they good to eat ?" asked Pencroft.
"Perfectly so." "Then let us eat some lithodomes." The sailor could rely upon Herbert; the young boy was well up in natural history, and always had had quite a passion for the science.

His father had encouraged him in it, by letting him attend the lectures of the best professors in Boston, who were very fond of the intelligent, industrious lad.

And his turn for natural history was, more than once in the course of time, of great use, and he was not mistaken in this instance.

These lithodomes were oblong shells, suspended in clusters and adhering very tightly to the rocks.

They belong to that species of molluscous perforators which excavate holes in the hardest stone; their shell is rounded at both ends, a feature which is not remarked in the common mussel.
Pencroft and Herbert made a good meal of the lithodomes, which were then half opened to the sun.