^P. sayana.^ Carapace little longer than broad; breadth about one quarter of an inch; smooth; has three acute denticulations between the eyes, the middle one the largest and depressed in the center; two denticulations on each anterior side; chelæ fringed with hair on the edges; walking-legs somewhat hairy; fifth pair of legs folded over base of carapace; color reddish, with white spots. This species was once called /occulata/, because of the eye-like spots over its entire surface. The posterior part and abdomen have longitudinal bands of color. The claws are marked like the shell. Found from South Carolina southward, often in the shells inhabited by hermit-crabs. (Plate LXI.) [pg270] GENUS ^Petrolisthes^ ^P. sexspinosus.^ Carapace longer than broad; breadth about one half of an inch; space between the eyes broad, but not divided into three teeth as in /Porcellana sayana/; second joint of the cheliped has five broad teeth on its front edge and five or six small spines on its outer edge; fifth pair of legs doubled over base of carapace; whole body traversed with broken red lines. Found from South Carolina southward. (Plate LXI.) ^P. armatus.^ Carapace longer than broad; breadth about one quarter of an inch; prominent and wide between the eyes; a small sharp spine on each anterior side; chelipeds long; second joint of cheliped twice as long as broad, with three teeth on the front edge and four or five small spines on the outer edge. Found on the Florida coast. (Plate LXI.) FAMILY ~LITHODIDÆ~ The species of this family have a broad, ovate, uneven body and a prominent rostrum. The fifth pair of legs are rudimentary and are folded under the carapace in the branchial chambers, so that the crabs appear to have but four legs on each side. This is the distinguishing feature of the family, and makes them easily recognized. GENUS ^Lithodes^ ^L. maia.^ The carapace is cordate (heart-shaped), and longer than broad, exclusive of the rostrum. The margin is recurved all around, and is beset with numerous very long spines. Six spines on each anterior side margin are regular and longer than the others. The surface of the carapace is covered with tubercles and spines and elevated in places. The rostrum is spiny, a third as long as the carapace, and has two spines at the base, one above the other, a spine at each side, two lateral spines near the middle, and two terminal divergent spines. The chelipeds are unequal and are covered with spines, those on the inner margin being the longer. The color is yellowish-red, lighter underneath; the spines are darker. Found on the fishing-banks off the coast of Maine. (Plate LXI.) [Illustration: PLATE LXI. 1, Hippa talpoida. 2, Albunæa gibbesii. 3. 1, Porcellana sayana; 2, Petrolisthes armatus; 3, Petrolisthes sexspinosus. 4, Lithodes maia.]