Page:Cape Cod (1865) Thoreau.djvu/115

Rh nidus, called "sand-circle," looking like the top of a stone jug without the stopple, and broken on one side, or like a flaring dickey made of sand-paper. Also,

Cancellaria Couthouyi (?), and

Periwinkles (?) (Fusus decemcostatus).

We afterward saw some other kinds on the Bay side. Gould states that this Cape "has hitherto proved a barrier to the migrations of many species of Mollusca."—"Of the one hundred and ninety-seven species [which he described in 1840 as belonging to Massachusetts], eighty-three do not pass to the South shore, and fifty are not found on the North shore of the Cape."

Among Crustacea, there were the shells of Crabs and Lobsters, often bleached quite white high up the beach; Sea or Beach Fleas (Amphipoda); and the cases of the Horse-shoe Crab, or Saucepan Fish (Limulus Polyphæmus), of which we saw many alive on the Bay side, where they feed pigs on them. Their tails were used as arrow-heads by the Indians.

Of Radiata, there were the Sea Chestnut or Egg (Echinus granulatus), commonly divested of its spines; flat circular shells (Scutella parrna?) covered with chocolate-colored spines, but becoming smooth and white, with five petal-like figures; a few Star-fishes or Five-fingers (Asterias rubens); and Sun-fishes or Sea-jellies (Aureliæ).

There was also at least one species of Sponge.

The plants which I noticed here and there on the pure sandy shelf, between the ordinary high-water mark and the foot of the bank, were Sea Rocket (Cakile Americana), Saltwort (Salsola kali), Sea Sandwort (Honkenya peploides), Sea Burdock (Xanthium echinatum), Sea-side Spurge (Euphorbia polygonifolia); also, Beach Grass