Observations on the genus Ocythoë of Rafinesque, with a description of a new species

Several ancient and modern writers have described a species of Ocythoë often found in the Paper Nautilus, and have considered it as belonging to that shell. Sir Joseph Banks and other naturalists have maintained a contrary opinion, and have considered the Ocythoë as a parasitical inhabitant of the Argonaut’s shell. Rafinesque, whose opportunities for observation were commensurate with his talent in observing, regarded it as a peculiar genus, allied to the Sepia octopodia of Linnæus, and as a parasitical resident of the above-mentioned shell. The observations of the late Mr. John Cranch, zoologist to the Congo expedition, have, in the opinion of Dr. Leach, removed all doubt upon this subject. In the Gulf of Guinea he took several specimens of a new species of Ocythoë in a small Argonauta, and placed two of them in a vessel of sea-water, so as to observe their motions. When adhering to the basin the shell could be removed; they had the power both of retiring within it and of entirely quitting it. One having left the shell lived several hours, and showed no de­sire to return. Others quitted the shell while taking up the net. Ocythoë differs from the Polypus in the shortness of its arms; in having pedunculated instead of simple suckers; in having four ob­ long spots on the inside of the tube, and a small fleshy short tubercle immediately above the bronchiee, on each side,—a character common to this genus, to Loligo, and to Sepia, but which does not exist in Polypus.