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Show 144 ClttJST AC£A. from the second, is an elongated and movable spine, six on each side: Inclosed in the inferior cavity, and disposed in pairs on two longitu: nal ranges, are ten fin-like feet, almost similar in form to the two last but simply united at base, laid one on the other, and bearing 0 ' their posterior face, the branchire which appear to be compos:d 0~ numerous and crowded fibres arranged on the same plane one against the other. The anus is situated at the inferior root of the stylet terminating the body. According to an observation communicated to us by M. Straus, we only find in the interior of the first shield besides the brain, a single sub-resophagal ganglion( 1 ). The tw~ nervous cords are then prolonged into the interior of the second shield, forming there, and at the origin of the branchial feet som • • ' e sma~l gangha, which send branches to those organs. According to Cuvier, the heart, as in the Stomapoda, is a large vessel furnished internally with fleshy columns, extending along the back, and giving out branches on both sides. A wrinkled resophagus, ascending in front, leads to a very muscular gizzard, lined with a cartilaginous kind of velvet, studded with tubercles, and followed by a wide and straight intestine. The liver pours its bile into the intestine by two d.u cts. on each side. A great portion of the shell is filled by the . ~ ova ries In the •emale, and by the testes in the male. These animals are sometimes found two feet in length; they inhabit the seas of hot climates, and most generally frequent their shores. They appear to me to be proper to the East Indies and the coast of America. The species found in France-L. cyclops-is commonly called the Casserole(2), from its having some resemblance to th ~orm of that utensil, anrl because when the feet are removed its she!~ IS used .to h?ld water •. Major Le Conte, one of the most intelligent of naturalists In the Umted States, and who has so largely contributed to advance the science of entomology by his discoveries and researches, states that it is given to the hogs. Savages employ the stylet of the tai.l to point their arrows, which, thus armed, are much dreaded .. The1r eggs are eaten in China. When these animals walk, their feet are not seen. Fossil specimens are found in certain strata of a moderate antiquity(3). (1) The two anterior feet may represent the mandibles of the Decapoda the fou. r following ones their J. aws • and th e 1a st · · · ' SIX the1r foot-Jaws; those of the second sh,eld would correspond to the thoracic feet. (2) The King-crab of our fisher 1 T.r. men, or t 1e .u.orse-alwe. Very common on the coast of New Jersey. .11m. Ed. (3) Knorr, Monum. of the Deluge I 1 vrv · It would f1 h • • P · .,n.. ; Desmar., Crust. fossil., XI, 6, 7. seem •·om t ese figures th at th e 1l ltera 1 spm. es of the second piece of the P.I£CILOPODA. 145 I e the four anterior feet, at least in one of the sexes, are n som' terminated by a single t?e. f h' d' • . . k . . h L. But a single species o t IS I VISion IS nown; 1t IS t e tmu- 1 heterodactylus, and is the type of the genus Tachypleus, L" each(!). I have seen it figured on Chm. ese vel1 u rns. In the others, the two anterior claws at most, are alone monodac- , 1 All the ambulatory feet are didactyle, at least in the females. Ttyh e'. division is composed o f severaI speci. es, w I ' h . h HC , owmg to t e !itt:: attention that has been paid to the detailed form of the~r parts, the differences resulting from sex and age, and from their pecu-ltoia t b . . d . . d localities, have not yet een characteru;e m a r1gorous an comparative manne.r.. The com~on American Limulu~ for instance, when young, is whitish or of a hght colour, and has SIX stout teeth along the whole ridge of the middle of the upp~r shell, and ~wo others equally strong and pointed on each lateral r1dge of the shield or of the first piece of that shell; while older specimens, sometimes more than a foot and a half in length, are of a deep brown colour or almost blackish, their teeth, the middle ones especially, being almost obliterated. Here also the lateral margins of the second piece of the shell are marked with fine dentations which are scarcely ap· parent or wanting in the former. We should consider as young individuals the Lim. cyclops, Fab., and the L. Sowerbii, Leach, Zool. Miscell., LXXIV; his L. tridentatus, and the L. albus, Bose.: and as older ones, my Limule des Moluques; Monoculus polyphemus, L.; Clus., Exot., lib. VI, cap. xiv, p. 128; Rumph., Mus., XII, a, b, which I at first considered a distinct species, under the belief that these large individuals inhabited those islands exclusively. In all of them, or at all ages, the tail is somewhat shorter than the body, and triangular, the upper r!dge finely denticulated and without any decided sulcus beneath. We will designate this species by the name of Limulus polyphemus. These latter characters will distinguish it from some others described by Dr Leach(2). shell, in lieu of spines, merely form smaller teeth articulated at base; but these articulations have perhaps disappeared. (1) This Limulus is perhaps the Kabutogani or Unkia of the Japanese, and re· presents the constellation of Cancer on their primitive Zodiac. (2) See Nouv. Diet. d'Hist. Nat. Ed. IT; Desmar., Consid., p. 344-358. Vot. III.-T |
