A manual of the Mollusca, or, A rudimentary treatise of recent and fossil shells . Fig. 35. Nautilus. Fig. 36. Clymenia. Fig. 37. riiint-^.^ The air-chambers of the recent nautilus are lined by a very thin, li\aDgmermbrane; those of the fossil orthocerata retain indications of a thick vascu-lar lining, connected vd\h. the animal by spaces between the beads of thesiphuncle. t The bodij-chamher is always very capacious; in the recent nautilus itscavity is twice as large as the whole series of air-cells ; in the goniatite (), it occupies a whole whirl, and has a considerable lateral extensi
A manual of the Mollusca, or, A rudimentary treatise of recent and fossil shells . Fig. 35. Nautilus. Fig. 36. Clymenia. Fig. 37. riiint-^.^ The air-chambers of the recent nautilus are lined by a very thin, li\aDgmermbrane; those of the fossil orthocerata retain indications of a thick vascu-lar lining, connected vd\h. the animal by spaces between the beads of thesiphuncle. t The bodij-chamher is always very capacious; in the recent nautilus itscavity is twice as large as the whole series of air-cells ; in the goniatite (), it occupies a whole whirl, and has a considerable lateral extension; andin ammonites communis it occupies more than a Fig. 38. Ammonites. Fig. 39. ? Fig. 35. Nautilus pompilius, L. Fig. 36. Clymenia striata, Miiust., see pi. II.,fig. 16. Fig. 37. Hamites cylindraceus Defr., see fig. 58. f The apocryphal genus spougarium, was founded on detached septa of an orih^i-ceras, from the Upper Ludlow rock, in which the vascular markings distinctly radiatefrom tiie siphuncle. Mr. Jones, warden of Clun Hospital, has several of these inapposition. J Fig. 38. Section of ammonites ohtusus, Sby. lias, Lyme Regis; from a verj youngspecimen. Fig. 39. Section of goniatites sphcericus, Sby. carb. limestone, Bolland (inthe cabinet of Mr. Tennant.) The dotted lines indicate the lateral extent of the body-chamber. 80 MANUAL OF THE MOLLIJSCA. The margin nf the aperture is quite simple in the recent nautihis, andaffords no clue to the many cmious modifications observable in the fossilforms. In the ammonites we frequently find a dorsal jDrocess, or lateral pro-jections, developed periodically, or only in the a
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectmollusks, bookyear185
