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Show 316 MOLLUSCA. 'rhe SoAPHITEs, Sowerb., arc those in which the whorls are con. tiguous and in the same plane, the last one excepted, which is de. tached and reflexed on itself(l). Some, BAcULITEs, Lam., are entirely straight without any spiral portion whatever. Some of them are round(2), and others compressed(3). The last sometimes have a lateral siphon. The first cells of some of them-the HAMITES, Sowerb., are arcu. a ted. Finally, tho.se which vary most from the usual form of this family are the TuRRILITEs, Mon tf., 118, where the whorls, so far from run· ning in the same plane, suddenly descend, giving to the shell that form of an obelisk which is called turreted( 4). It is also thought, and from similar considerations, that we should refer to the Cephalopoda, and consider as internal shells the CAMERINEs, Brug.-N UMMULITEs, Lam. Commonly called Nummulites, lenticular stones, &c. which are only found among fossils, and present, externally, a lenticular figure without any apparent opening, and a spiral cavity internally, di· vided by septa into numerous small chambers, but without a siphon. They constitute the most universally diffused of all fossils, forming, per se, entire chains of calcareous hills and immense bodies of build· ing stone( 5). The most common, and those which attain the greatest size, form a complete disk, and have only a single range of cells in each whorl(6). (1) Sc. obliquus, Sowerb . .; Cuv., Oss. Foss., II, part II, pl. ii, f. 13. (2) Baculite3 vertebralis, Montf., 342; Fauj., Mont. de StPierre, pl. xxi. (3) The Timnite, Montf., 346; Walch., Petrif., Supp., pl. xii, constitutesthe genus RHABDITF.S of Haan, who refers the lcTHYOSAncoLITES of Desmar. to it. (4) Montf. Journ.de Phys.,an VII, pl. i, f. 1. There are some doubtsastothe position of the siphon. Perhaps, as M. Audouin observes what has been taken for it, is the columellar convolution. ' (5) !he stone termed pierre de Laon is whol(y formed of Nummulites. The pyramtds ~f Egypt are placed upon rocks of this description, which also furnished the matertals of the superstructure. See the Memoir of Fortis on the Discolitu in his work on Italy, and that of M. Hericart de Tltury, as well as Lam., .!J.nim. san8 Verteb., VII~, and M. D'Orbigny, Tab. Method. des Cephalopodes. (6) Nautdus mammilla, Ficht., and M:oll. VI a b c d·-Naut. lenticularU, VI' e ' f.' g, 11 ' VII, a-h. To tht· s genus also' we ' ref'e r t' he' Lx' coPHRE and Ea:EONE, Montf., 158, 166, and his RoT.A.LITE, 162, which differs from the RoTAtn:s of La· mar.ck. CEPHALOPODA. 317 Some very small species are also found in certain seas( 1 ). The margin of other small species, (the SIDEROLITI-IEs, Lam.,) both fossil and living, are bristled with points which give them a stellated appearance(2). The labours and researches, fruits of an infinite patience, of Bianchi( or Janus Plancus), Soldani, Fichtel, Moll, and D'Orbigny, have ascertained an astonishing number of these chambered shells without a siphon, like the Nummulites, that are extremely small and frequently microscopical, both in the sea, among the sand, fucus, &c. and in a fossil state in the sand formations of various countries. They vary in a remarkable degree as to their general form, the number and relative position of the chambers, &c. In one or two species, the only ones whose animals have been observed, there appears to be a small oblong body crowned by numerous and red tentacula, which, added to the septa of the shell, have caused them to be placed immediate! y after the Cephalopoda, like .the genera just mentioned. This arrangement, however, requires to be confirmed by more numerous observations before we can consider it as final. Such of these species as were known in the time of Linnreus and Gmelin were placed by those naturalists among the Nautili. M. D'Orbigny, who has exceeded every other person in attention to this subject, forms them into an order which he calls FoRAMINIFERA, on account of the only communication between the cells being by means of holes, and divides them into families according to the manner in which the cells are disposed. When the cells are simple and spirally arranged~ they constitute his HELIOOSTEGA, which are again subdivided. If the whorls are enveloped, as is particularly the case in the Nummulites, they become his HELIOOSTEGA NAUTILOIDA(3). (1) Nautilus radiatus, Ficht. and Moll., VH, a, b, c, d;-Naut. venosus, lb., e, f, g,h. (2) Siderol. calcitrapoi'de, Lam., Fauj., Mont. de StPierre, pl. xxxiv. (3} These infinitely small beings having but little to do with our plan, we will merely cite the' names of the genera with a few examples. The Nummulites themselves are compressed in this first division under the name of NuMMULINEs,Nautilua pompiloi'des, Fich., and Moll., N. incrasaatus, Id. The SYDEROLINA, the same as the Syderolites, Lam. CmsTELLARIA,-Nautilus cassia, Naut. galea, Id., &c. RonuLINA,-Nautilus calcar, Naut. vortex, Id. SPIROLINA,-Spirolinite3 cylindracea, !.am., Anim., sans \'ertcb. PENEROPLA,-Nautilus planatus, Fitch. and Moll., &c. D:&NTRITINA, POLYSTOMELT,A, ANOJ\[ALINA, \ |
