A short description of five (supposed) new species of the genus An Account of an American species of TORTOISE, not noticed A new genus of Fishes, of the order Abdominales, proposed un- An Account of the CRUSTACEA of the United States, continued. CATOSTOMUS, a new genus of Fishes, concluded. An Account of two new genera of Plants; and of a species of TILLEA, and another of LIMOSELLA, recently discovered Barbadoes to Santa Cruz, inclusive. By Wm. Maclure. Observations on several species of the genus ACTINIA; illus- trated by figures. By C. A. Le Sueur. An Account of the CRUSTACEA of the United States, continued. THE members of the Academy of Natural Sciences of Philadelphia, desirous of acquiring knowledge themselves, and extending it among their fellow citizens, have for some years been accustomed to meet at leisure hours for the purpose of communicating to each other such facts and observations, as are calculated to promote the views of the society. By degrees, a collection of subjects in natural history was made, and has increased until a museum has been formed, which is already very valuable, and which is daily increasing. In further pursuance of the objects of their institution, the Society have now determined to communicate to the public, such facts and observations as, having appeared interesting to them, are likely to be interesting to other friends of natural science. They do not profess to make any periodical communication; but well knowing how desirable it is, that persons engaged in similar pursuits, should be made acquainted as early as possible with what has been done by their fellow-labourers in the fields of science elsewhere, they mean to publish a few pages whenever it appears to them that materials worthy of pub lication have been put in their possession. In so doing, they propose to exclude entirely all papers of mere theory,—to confine their communications as much as possible to facts-and by abridging papers too long for publication in their original state, to present the facts thus published, clothed in as few words as are consistent with perspicuous description. Well aware that much leisure and superfluous wealth are not always found in company with an ardent love of science, they mean their proposed publication to be as cheap and as unostentatious as the nature of the subjects will admit; so that it need not encroach unnecessarily on the funds of the society, or of those who may wish to purchase it. In short, they are desirous of contributing their share to the mass of knowledge, as early in all cases, and with as little show, and as small expense as possible. The present publication will be a specimen of what they propose in future. They invite the lovers of science generally, and particularly all those who are anxious for its encouragement in the United States, to aid in promoting the objects of this institution, and to encourage the present publication, so long as the contents of it shall prove deserving of public approbation. All papers intended for publication in this Journal, must be post paid, and directed, under the proper signatures of the authors, to the Academy of Natural Sciences, No. 35 Arch-street, Philadelphia. Description of six new species of the genus FIROLA, observed by Messrs. Le Sueur and Peron in the Mediterranean Sea, in the months of March and April, 1809 By C. A. Le Sueur. With a Plate. MOLLUSCA PTEROPODEA†. Character. Body free; furnished with fins for swimming; head distinct. A. PTEROPODES NAKED. Character. Destitute of a gelatinous, horny, or calcareous shell. *No TENTACULA. Genus.-FIROLA. Char. Jaws horny; eyes two; fins 1, 2, 3; branchia plumose, floating freely beneath the body, and grouped with the heart, around an oblong nucleus at the base of the tail. The body is elongated, cylindrical, of a gelatinous, diaphanous consistence, and of a pale colour. Tail distinguished from it by a groove, one fourth the length of the body, compressed, more or less carinated, and laterally serrated, terminated by a lobed fin, and sometimes with a moniliform, elongated appendage. Eyes composed of a brilliant hyaline globule, supported by a small peduncle, which arises from a black concave or convex cup, placed at the junction of the rostrum with the body. Several small gelatinous points, before and above the eyes, serving probably to assist in retaining the molluscous prey in † Vid. Annal. du Museum d'Hist. Nat. T. 14 and 15. order that it may be the more easily devoured, when pressed between them and the jaws. Rostrum one fourth the length of the body, somewhat contractile, moveable in every direction, enlarged at the tip to receive the retractile jaws; which are opposite, and armed with a series of horny curved points ranged upon each jaw like the teeth of a comb, with a row of smaller ones between them, and furnished at the base with a longitudinal lip. Immediately behind the jaws, on the interior, are two capitate threads connected by nerves; adjoining these are two palpiform biarticulate processes; first joint very : short, oblique; second elongated, recurved; probably used by the animal as interior palpi. Nervous System. A nervous ganglion of four rounded lobes is situated between the eyes and the œsophagus, giving rise to several nervous filaments; the four principal ones, arise each from the extremity of a lobe; two of them terminate in the jaw, and the other two are directed backwards to the tail, but interrupted at the base of the dorsal fin by a double, oblong, lobated, ganglion. The centre of the first ganglion furnishes two nerves for each eye, of which one terminates at the base of the peduncle, and the other, much smaller, at the pupil. Numerous smaller nerves arise from each of these nervous ganglions, directed to different parts of the body. Viscera. Nucleus oblong, pyriform. Colour iridescent, when at the depth of three, four, or five feet in the water, it is resplendent, diamond-like. A large cylindrical canal, more or less dilated, attached to the throat at the anterior extremity, supported near and above the eyes by a membranous diaphragm, passing loosely through a large cavity of the body, and embracing at its termination |